GIFT  OF 


No.  1755 


^ 


a. 


b'^ 


GUN  MAKING 

IN  THE  UNITED   STATES 


By 

CAPTAIN  (NOW  COLONEL) 

ROGERS  BIRNIE,  Jr. 

ORDNANCE  DEPARTMENT 
U.  S.  ARMY 


REPRINTED  FROM  THE  JOURNAL  OF  THE  MILITARY 

SERVICE  INSTITUTION,  BY  ITS  AUTHORITY, 

WITH  CORRECTIONS  BY  THE  AUTHOR 


WASHINGTON 

GOVERNMENT  PRINTING  OFFICE 
1907 


War  Department, 

Document  No.  298. 

Office  of  the  Chief  of  Ordnance. 


(Form  No.1755.) 


THE   OFFICIAL   NUMBER  OF   THIS   COPY 


IS  9 


The  Commanding  Officer  or  Post  or  District  Ord= 
nance  Officer  to  whom  this  copy  is  issued  will  be  held 
personally  responsible  for  its  safe=keeping.  When 
another  officer  relieves  him  a  receipt  for  it  by  number 
will  be  taken,  which  should  be  mailed  to  the  CHIEF 
OF  ORDNANCE,  U.  S.  Army,  Washington,  D.  C. 


1363 
TABLE   OP   CONTENTS. 


^ 


Page. 
Preface 7 

I. 

Introductory 9 

Abandonment  of  cast-iron  rifles. — Conservative  course  of  legislation. — Dif- 
ficulty of  perfecting  a  new  type  of  gun. — Early  inventions. — Treadwell's 
coiled  and  ring-welded  guns. — Hooped  guns. — Origin  of  slotted-screw 
breech  mechanism. — Broadwell  gas  check. 

Initial  tension  in  cast-iron  guns 14 

Eodman  method  of  casting. — Inadequac)'  of  old  method  of  determining 
initial  tension  in  castings. — New  methods  described. 
Cast-iron  smoothbore  guns  in  service. — Parrott  rifles 17-18 

II. 
Period  from  1872  to  1881 20 

Systems  recommended  by  Heavy  Gun  Board  of  1872. — Hitchcock,  Mann, 
and  Lyman- Haskell  guns. — Woodbridge  brazed  wire  gun. 

Converted  muzzle-loading  rifles 22 

Strength  of  the  converted  guns. — Wrought-iron  and  steel  tubes  of  Ameri- 
can manufacture. — Table  showing  endurance  of  experimental  and  type 
guns. 

Converted  breech-loading  rifles 27 

Success  of  experimental  8-inch  rifle. — Failure  of  8-inch  and  11-inch  cham- 
bered rifles. — Trial  of  8-inch  chambered  rifle  with  rounded  angles  in 
slot. — Rejection  of  steel  forgings  for  12-inch  guns. — Unfavorable  opin- 
ions of  gun  steel. 

Sutcliffe  9-inch  B.  L.  rifle.— Thompson  12-inch  B.  L.  rifle 29-31 

Field  guns 31 

Dean  3.5-inch  mandrilled  bronze  gun. — Sutcliffe  3-inch  B.  L.  rifle. — Mof- 
fatt  3-inch  B.  L.  rifle. — Converted  3.2-inch  B.  L.  chambered  rifle. 
Review  of  the  ten  years  ending  in  1882 33 

III. 

Boards  and  committees  appointed  by  Congress 35 

Their  conclusions  regarding  forged  steel  for  guns  and  Government  gun 
factories. — Helpful  legislation  for  the  Navy. — Money  expended  by  Army 
Ordnance  Department  for  procurement  of  cannon  during  twenty  years. 

Recent  plans  of  gun  construction. — Systems  recommended 37 

The  multicharge  gun. — Mann  breech  mechanism. — Yates  breech  mechan- 
ism.— The  slotted-screw  breech  mechanism. — Reason  favoring  its  adop- 
tion. 

IV. 

Cast-iron  rifles 48 

Rodman  rifles  made  1861  to  1869.— Tests  and  endurance  of  Rodman  rifles. — 
Experiment  to  test  effect  of  blows  upon  pressure  gauge. 

Atwater  12-inch  rifle. — Wiard's  cast-iron  rifles  at  Nut  Island 50-51 

12-inch  B.  L.  cast-iron  rifle,  model  of  1883 51 

Firing  tests  and  endurance. — Erosions  of  the  bore. — Claims  to  improve- 
ment in  metal  and  methods  of  casting  discussed. — Time  required  to 
make  large  gun  castings. — Conclusions. 

3 


523510 


4  TABLE   OF   CONTENTS. 

V.  Page. 

Combined  cast-iron  and  steel  guns 58 

12-inch  rifled  mortars,  steel  hooped. — Tests  of  the  M.  L.  mortar. — Pre- 
liminary firings  with  B.  L.  mortar. — Construction  of  the  rifled  mortars. — 
Steel  hoops  needed  to  give  sufficient  strength. 

12-inch  B.  L.  rifles 61 

Cast-iron  gun  lined  with  half  tube  of  steel. — Steel  hooped  and  tubed  gun, 
with  cast-iron  body. 

Wire  guns  of  recent  design 62 

10-inch  wire- wrapped  cast-iron  rifle. — 10-inch  steel  rifle,  longitudinal  bars, 
wire  wound. — Merits  of  wire-gun  construction  not  yet  decided. 

VI. 

Steel  cast  guns 65 

Two  6-inch  guns  to  be  made. — Weights  and  special  plant  required  for  large 
gun  castings. — Defects  of  castings. — Proposed  methods  of  casting. — 
Elastic  strength  of  neutral  piece. — Utility  of  initial  tension. 

VII. 

Built-up  forged  steel  guns.  — Claims  of  American  inventors 70 

Amount  of  gun  forgings  procured  by  Army 71 

Progress  made  in  construction  of  guns. — Physical  qualities  of  steel  for- 
gings.— Superiority  as  a  metal  for  guns. 

Elastic  strength  of  guns 74 

Relative  strength  of  homogeneous  guns. — Composite  guns. 

Experiments  made  by  Army  Ordnance  Department 78 

Superiority  of  oil-tempered  and  annealed  steel. — Similitude  of  specimen 
and  shrinkage  tests. — Result  realized  in  a  complete  gun  cylinder. — Veri- 
fication of  formulas. — Effect  of  temporary  exposure  to  high  heat  upon 
qualities  of  forgings. — Frictional  resistance  to  longitudinal  separation  due 
to  shrinkage. — Tests  of  forged  trunnion  hoop  of  American  manufacture. — 
Efficacy  of  annealing  in  removing  stains  from  forgings. 

Firing  tests  of  steel  guns 86 

3.2-inch  B.  L.  field  guns. — 5-inch  B.  L.  siege  rifle. — 7-inch  B.  L.  siege 
howitzer. — 8-inch  B.  L.  steel  rifle. — Accuracy  and  high  power. 

Work  done  by  the  Navy 89 

Amount  of  forgings  procured  and  under  contract  with  Midvale  Steel  Com- 
pany and  Bethlehem  Iron  Company. — Number  of  guns  made  or  provided 
for. — Fabricating  capacity  of  the  Washington  Navy- Yard. — Tests  of 
guns. — Dimensions,  weights,  charges,  and  high  power. 

Replies  to  criticisms  of  construction  of  built-up  steel  guns 91 

Commercial  advantages  of  gun  and  armor-forging  plant 93 

The  pneumatic  dynamite  torpedo  gun 96 

Appendix  A.   Steel  forgings  produced  by  Midvale  Steel  Company  and  the 

Cambria  Iron  and  Steel  Works 97 

Appendix  B.  Initial  tension  in  gun  construction,  discussed  for  a  steel  cast  gun.         98 
Appendix  C.  Alleged  failures  of  steel  guns. — Reply  to  report  of  Chamber  of 

Commerce,  New  York  City,  dated  February  3,  1887 108 

Illustr.\tions. 

Plate  III.  8-inch  B.  L.  steel  rifle To  face  Preface. 

Initial  tension  in  cast-iron  gun  cylinder 16 

Plate  IV.  Pressure  and  strains  in  gun  of  solid  wall 76 

I.  Shrinkage  tests  of  steel  gun  hoop 79 

II.  Shrinkages  in  full  section  of  a  built-up  gun 81 


DISCUSSION. 

Page. 

Lieut.  Commander  F.  M.  Barber,  U.  S.  Navy 115 

Bvt.  Brig.  Gen.  H.  L.  Abbot,  Corps  of  Engineers 116 

Bvt.  Maj.  J.  B.  Campbell,  captain,  Fourth  Artillery 117 

Joseph  Morgan,  Jr.,  Johnstown,  Pa 119 

Theodore  Cooper,  C.  E.  ,  New  Yoi*k 120 

J.  R.  Haskell,  Esq 121 

Capt.  Charles  Shaler,  Ordnance  Department 124 

Lieut.  E.  M.  Weaver,  Second  Artillery 124 

William  E.  Woodbridge,  Esq 126 

Capt.  0.  E.  MiCHAELis,  Ordnance  Department 127 

Prof.  R.  H.  Thurston,  Cornell  University 129 

James  E.  Howard,  C.  E.  ,  Watertown  Arsenal 131 

Commander  R.  D.  Evans,  U.S.  Navy 133 

Capt.  John  G.  Butler,  Ordnance  Department 133 

Lieut.  William  Crozier,  Ordnance  Department 137 

Capt.  Rogers  Birnie,  Jr.,  Ordnance  Department 140 

5 


8  INCH  B.L.  STEEL  RIFLE. 

WEIGHT  13  TONS. 


charge 113  pounds. 

le  (3|  caliberalong) 300  pounds, 

wnsiivuf  loadinir 1  (unity). 

Muzzle  velocity 1,852  feet  peraecond. 

Muzzle  energy 7. 133  fool-tons. 

Pressure 36,000  pound8(16  tons t. 


r;i;i— OS.    cr..  fa.-f  page  7.) 


PREFACE. 

As  a  preface  to  that  which  follows,  it  is  proper  to  state  that  the 
conclusions  and  opinions  expressed,  except  when  otherwise  stated, 
represent  the  opinions  of  the  writer  and  have  no  official  sanction. 
The  subject-matter  aims  to  be  a  history  of  the  progress  of  gun  making 
and  gun  trials  in  the  United  States,  especially  with  reference  to  the 
part  taken  therein  by  the  War  Department,  in  the  past  fifteen  years 
or  from  the  date  of  the  Heavy  Gun  Board  of  1872 ;  and  prior  to 
that  of  such  matters  as  appear  to  have  a  bearing  on  current  questions 
of  gun  construction.  The  prominent  part  taken  by  the  Navy  Depart- 
ment in  being  the  pioneer  of  built-up  forged  steel  guns — thanks  to  its 
energetic  efforts  backed  up  by  liberal  and  progressive  Naval  Com- 
mittees of  Congress — deserves  the  fullest  recognition,  and  if  a  com- 
paratively brief  mention  is  made  of  the  operations  of  that  Depart- 
ment in  general  it  will  be  understood  as  due  to  the  force  of  circum- 
stances which  render  even  a  somewhat  detailed  account  of  matters 
with  which  the  writer  is  most  familiar  a  matter  requiring  all  the 
time  and  attention  at  his  disposal.  The  data  given  have  been  collected 
from  official  reports  or  otherwise,  with  every  regard  for  correctness. 
The  chronological  order  adopted,  for  this  description  of  events  has 
led  to  a  much  more  extended  treatise  than  was  at  first  intended 
and  perhaps  also  to  repetitions  which  may  appear  unnecessary;  but 
this  order  having  an  advantage  in  respect  to  the  time  necessary  to 
devote  to  the  preparation  of  the  paper  has  been  adhered  to. 


COPYRIGHT. 

THE  MILITARY  SERVICE  INSTITUTION. 

1888. 
Republished  by  its  Authority,  1907. 


GUN  MAKING  IN  THE  UNITED  STATES." 


Introductory — Early  Inventions — Rodman  Method  of  Casting — • 
Smoothbore  Guns — Parrott  Rifles. 

By  Capt.  Rogers  Birnie,  Jr..  U.  S.  Army.  Orcliiauce  r>ei)artiuent. 

Within  the  past  few  years  the  constituted  authorities  of  both  the 
Army  and  Navy  have,  with  a  marked  unanimity  of  opinion,  advo- 
cated the  construction  of  built-up  steel  guns  and  have  entered  upon 
their  manufacture  to  the  extent  of  available  appropriations  by  Con- 
gress. Until  this  time,  with  the  exception  of  the  Ordnance  system 
of  converted  guns,  the  art  of  gun  making  in  the  United  States  made 
slow  progress,  compared  with  the  rest  of  the  world,  from  the  time 
when  our  Rodman  and  Dahlgren  cast-iron,  smoothbore  guns  reached 
their  best  development  and  gave  us  a  brief  period  of  superiority. 
That  was  some  twenty-five  years  past,  and  the  guns  we  have  avail- 
able for  seacoast  defense  to-daj-  comprise  these  same  smoothbore 
guns,  supplemented  only  by  a  limited  number  of  the  converted 
muzzle-loading  rifles,  which  date  back  to  1872,  and  are  now  classed 
as  guns  of  third-rate  power.  The  same  was  true  of  our  field  artil- 
lery; but  in  this  respect  much  has  been  accomplished,  and  work  is 
now  in  progress  that  will  give  us  at  least  a  limited  supply  of  the 
best  class  of  modern  light  field  guns.  In  small  arms,  and  machine 
guns  firing  small  ammunition,  only  has  the  United  States  main- 
tained an  advanced  position. 

The  reason  for  this  state  of  affairs  is,  I  think,  easy  to  discern. 
The  trade  in  munitions  of  war  must,  like  every  other  industry,  obey 
the  inevitable  law  of  supply  and  demand.  The  demand  for  small 
arms  for  general  use  in  our  own  country,  and  the  fact  that  the  cost  of 
the  development  of  these  arms  places  the  matter  within  reasonable 
control  of  private  industry  and  does  not  necessitate  a  very  considerable 
expenditure  on  the  part  of  the  Government,  has  maintained  the  nec- 

oRead  before  Military  Service  Institution  November  26,  1887,  Major-General 
Schofield  in  the  chair. 


10  GUN    MAKING    IN    THE    UNITED   STATES. 

essary  skill  in  the  art  and  has  enabled  our  private  makers  to  com- 
pete successfully  in  the  markets  of  the  world.  With  guns  of  a 
heavier  caliber  the  case  is  very  different.  Governments  alone  need 
a  supply  of  these,  and  governments  alone  can  create  a  demand  for 
them.  The  close  of  the  civil  war  found  us  with  an  established  sys- 
tem of  smoothbore,  cast-iron  guns  possessing  great  merit.  But 
hardly  had  we  time  to  congratulate  ourselves  upon  this  circumstance 
before  the  advance  of  foreign  poAvers  in  the  manufacture  of  rifled 
guns  forced  us  to  admit  our  inferiority.  We  all  know  the  result  of 
the  struggle  which  established  the  relative  merit  of  smoothbore  and 
rifled  guns.  We  placed  implicit  confidence  in  cast  iron  as  a  metal 
for  cannon,  and  so  continued  for  a  number  of  years  to  use  that 
metal  in  endeavoring  to  establish  a  system  of  rifled  guns,  while 
other  nations  Avere  coming  to  discard  it  more  and  more  in  favor  of 
Avrought  iron  and  especially  steel.  Our  first  rifled  guns,  introduced 
in  1861,  Avere  made  of  cast  iron<  and  a  limited  degree  of  success  was 
obtained;  then  others  were  tried,  with  signal  failure,  and  the  attempt, 
for  the  time  being  at  least,  fell  flat.  In  Congress  the  culmination 
of  the  matter  was  reached  in  the  terrific  report  of  the  Select  Com- 
mittee on  Ordnance,  1869.  And  in  the  War  Department,  in  his 
annual  report  for  1871,  the  Chief  of  Ordnance  said :  "  The  results 
obtained  Avill  not  warrant  me  in  recommending  that  any  cast-iron 
rifle  guns  be  procured  for  arming  the  forts.'*  All  this  happened 
sixteen  years  since  and  should  have  been  conclusive,  yet  there  are 
not  Avanting  manufacturers  and  laymen  to-day  Avho  still  adA^ocate 
cast-iron  rifles.  Judging  from  the  course  of  legislation  since  that 
period,  it  appears  that  the  country  has  scarcely  yet  recoA'ered  from 
the  paralysis  occasioned  by  the  discoA'ery  that  our  justly  vaunted 
cast-iron  gun  metal,  Avhich  had  done  such  excellent  serAdce  in  the 
short  heav)'^  smoothbores,  Avas  not  a  reliable  metal  for  rifled  guns. 
We  haA'^e  been  stumbling  along  in  the  rear  ever  since.  The  idea 
that  if  Ave  were  to  have  guns  they  should  be  made  with  existing 
facilities  in  the  United  States,  unaccompanied  by  any  whole-hearted 
effort  to  improA'e  those  facilities,  has  ahvays  been  kept  to  the  front. 
It  has  retarded  our  progress  and  continues  to  do  so.  Certainly.  I 
say,  the  material  for  guns,  and  the  guns  themseh^es,  must  be  of  home 
production:  but  why  it  should  be  considered  of  such  doubtful  policy 
to  encourage  improA^ements  in  the  manufacture  of  material  and 
gims,  and  thereby  benefit  commerce  as  well,  is  a  position  which  is 
difficult  to  explain.  The  very  conservatiA^e  course  of  legislation  in 
Congress  in  past  years  has  been  explained  by  saying  that  the  rapidly 
changing  developments  in  guns  and  armor  Avould  enable  us.  by 
Availing  a  few  years,  to  take  up  the  subject  at  an  advanced  stage  and 
thus  derive  the  benefit  of  the  A'ast  amount  of  experimentation  con- 
tinuously being  carried  on  in  other  countries.     Meantime,  the  policy 


GUN    MAKING    IN    THE    UNITED    STATES.  11 

has  been  pursued  of  maintaining  a  show  of  organization  for  the 
SerAdce  and  in  testing  immature  inventions  of  various  designs;  and 
board  after  board  has  been  appointed  with  sufficient  frequency  to 
keep  the  matter  in  apparentl}^  w^ell-meant  agitation.  Finally,  a 
climax  has  been  reached;  we  are  now  in  a  position  to  know  that 
navies  have  been  established  throughout  the  world  which  must  exist 
for  years  to  come,  and  that  equally  with  this  the  consensus  of  nations 
has  adopted  a  system  of  construction  for  guns  which  is  capable  of 
overcoming  these  vessels  and  is,  besides,  the  strongest  and  most 
reliffble  ever  made.  In  shooting  qualities  and  endurance  this  sys- 
tem— the  built-up  steel  gun^s  to-dav  without  a  rival,  and  as  long 
as  these  qualities  remain  essential  to  a  gun  it  promises  to  remain 
equal  to  the  best.  These  facts  have  been  exploited  for  several  years 
and  gain  new  confirmation  every  day.  Congress  has  given  no  appro- 
priation for  the  armament  of  fortifications  in  two  years  past,  and 
the  apparent  reasons  for  this  have  been  much  discussed.  The  com- 
mittees have  been  unable  to  decide  for  themselves  what  measures  to 
adopt.  Two  important  questions  were  under  consideration — first, 
as  to  the  kind  of  guns  that  should  be  provided,  and.  second,  the 
propriety  of  changing  the  present  methods  of  administration  in  the 
procurement  of  guns.  To  anyone  who  has  had  the  privilege  of 
appearing  before  these  committees  and  hearing  the  conflicting  char- 
acter of  the  testimony  taken,  the  wonder  is — supposing  that  equal 
weight  is  given  to  the  testimony  of  individuals,  as  appears  to  be  the 
case — the  wonder  is,  I  think,  not  that  the  committees  should  remain 
undecided,  but  it  would  be  strange  that  they  should  reach  any  con- 
clusion at  all.  As  to  the  proposed  change  in  the  method  of  admin- 
istration—taking away  from  the  present  organized  Bureau  of  the 
War  Department  the  control  of  these  affairs  and  creating  another 
bureau  under  the  same  Department  or  else  an  independent  commis- 
sion of  some  sort — -that  is  a  matter  about  which  Congress  will,  no 
doubt,  come  to  a  wise  conclusion.  It  is  a  question  of  the  substitu- 
tion of  one  set  of  agents  for  another,  or  of  a  multiplication  of  the 
paraphernalia  of  government.  It  does  not  seem  probable  that  the 
laws  will  be  so  changed  as  to  substitute  a  changeable  commission 
of  mixed  political  affiliations  for  the  individual  responsibility  now 
held  by  the  head  of  the  War  Department,  and  under  him  the  Chief 
of  Ordnance,  assisted,  as  he  is,  in  the  discharge  of  these  duties  by  a 
body  of  officers  already  trained  at  the  expense  of  the  Government, 
appointed  for  life,  and  subject  to  removal  onlj^  through  bad  behavior. 
This  much  we  may  at  least,  hope — that  the  question  of  what  guns 
the  Army  shall  use  will  remain  intrusted  to  military  men. 

But  the  main  question  before  us  is  as  to  the  type  of  gun  to  be 
adopted.  And  in  this  matter,  I  think,  we  should  make  a  very  clear 
distinction  between  an  existing  established  system  and  experimental 


12  GUN    MAKING    IN    THE    UNITED   STATES. 

construction.  By  all  means  let  experimentation  go  on,  only  this 
should  not  interfere  with  the  production  of  guns  for  service  when 
we  have  at  hand  the  highest  type  of  modern  gun,  the  outcome 
of  years  of  experimentation,  to  work  upon.  The  conception  of  a 
new  design  for  a  gun  is  a  very  small  part  of  its  successful  produc- 
tion; the  history  of  gun  making  abounds  in  new  designs  of  form 
and  material,  but  how  few  in  number  have  been  the  successful 
types.  It  is  a  very  small  matter  to  perfect  a  small  invention,  but 
to  even  approach  perfection  in  a  heavy  gun  is  one  of  the  most  ex- 
pensive and  laborious  questions  of  modern  times.  So  it  has  Jbeen 
proved  the  world  over,  and  so  it  has  been  shown  in  such  gun  trials 
as  have  been  made  in  the  United  States  in  recent  years,  wherein 
an  opportunity  has  been  afforded  for  the  test  of  a  number  of  differ- 
ent systems,  to  which  I  will  refer. 

In  reviewing  as  briefly  as  may  be  the  history  of  gun  making  in 
the  United  States  in  order  to  trace  its  effect  upon  questions  of  the 
day,  it  will  be  necessarj^  to  begin  a  connected  account  with  the  period 
of  Rodman's  improvements  in  making  cast-iron  smoothbores.  From 
that  period  up  to  the  present  era  of  steel  guns  we  will  follow  the 
chronological  order  of  the  trials  made  under  the  supervision  of  the 
War  Department. 

Some  of  the  earlier  designs  of  guns  possess  an  interest,  because 
of  the  successful  application  of  the  principles  involved  in  guns  now 
in  use.  Of  such  were  those,  dating  from  1841,  made  after  the  plans 
of  Daniel  Treadwell."  Professor  TreadwelFs  first  gun  was  made  of 
rings  or  short  hollow  cylinders  of  wrought  iron  joined  together 
end  to  end  by  welding.  Each  ring  was  made  of  several  thinner  rings, 
placed  one  over  or  around  the  other  and  welded.  Subsequently  the 
method  of  making  the  rings  was  someAvhat  changed  by  first  making 
a  single  ring  of  steel  about  one-third  the  thickness  of  the  whole 
and  upon  the  outside  of  this  winding  a  bar  of  iron  spirally,  as  a 
ribbon  is  wound  upon  a  block.  Machinery  Avas  devised  for  making 
the  rings,  Avelding  them  together,  and  forming  the  guns  by  means 
of  A^arious  molds,  dies,  and  sets  connected  with  a  powerful  hydrostatic 
press.  The  breech  was  closed  with  a  screw  plug,  and  a  trunnion  band 
formed  by  the  machinery  was  screAved  upon  the  outside  of  the  gun. 
The  object  of  this  method  of  manufacture  Avas  to  so  dispose  the 
metal  as  to  place  the  direction  of  the  fiber  in  opposition  to  tangential 
rupture. 

Professor  TreadAvell's  admirably  conceiA^ed  idea  Avas  to  make  a 
gun  of  equal  strength  in  all  directions.  He  demonstrated  the  propo- 
sition that,  proportioned  to  the  arena  of  resisting  metal,  the  tendency 
to  tangential  rupture  Avould  be  several  times  greater  than  the  ten- 

oA  short  account  of  an  improved  cannon,  and  of  the  machinery  and  processes 
employed  in  its  manufacture,  by  Daniel  Treadwell.  Cambridge,  1845. 


GUN    MAKING   IN    THE    UNITED    STATES.  13 

dency  to  transverse  rupture;  hence  he  arranged  the  metal  to  oppose 
its  lines  of  greatest  strength  to  the  effort  of  the  tangential  strains, 
and  thus  economized  his  material  and  approached,  as  nearly  as  coidd 
be  with  the  means  emploj-ed,  the  conception  of  his  ideal  gun  of  equal 
resistance.  These  guns  were  tested  both  by  the  Army  and  Navy. 
The  smaller  calibers  stood  well,  and  the  Ordnance  Board  in  1846 
recommended  batteries  of  6  and  12  pounders  and  12  and  '24  pounder 
howitzers,  approved  by  the  Secretary  of  War  in  1847.  Subsequently 
it  appears  some  guns  of  larger  caliber — 32  pounders — supplied  to  the 
Navy  did  not  prove  successful.  We  can  not  find  in  this  method  of 
construction  more  than  a  very  remote  resemblance  to  the  principles 
of  the  modern  built-up  gun,  but  its  development  was  directly  shown 
in  the  after  success  of  the  coil  systeui  of  wrought-iron  gun  construc- 
tion, illustrated  in  the  Armstrong  and  Woolwich  guns  of  the  period 
1856  to  about  1880,  the  breech  bands  of  the  Parrott  guns,  and  the 
coiled  welded  tubes  of  our  converted  guns. 

The  early  development  of  the  modern  system  of  hooped  guns  is 
traced  through  General  Frederix,  in  Belgium,  in  1830;  Thiery  in 
France,  whose  first  gun  was  constructed  in  1833;  Chambers'  Amer- 
ican patent  for  a  hooped  wrought-iron  gun,  dated  July  31,  1849, 
and  the  English  and  American  designers,  Blakely  and  Treadwell, 
in  1855.  Between  these  two  last  there  exists  a  question  as  to  priority 
of  the  principle  of  initial  tension  in  hooped  guns,  or  of  giving  to  the 
several  layers  of  hoops  such  a  shrinkage  as  would  cause  each  to  offer 
its  full  strength  in  resisting  the  action  of  an  interior  pressure  cal- 
culated to  rupture  the  gmi.  But  we  are  most  indebted,  I  believe,  to 
the  investigations  of  Lame  and  Barlow  for  the  origin  of  this  prin- 
ciple and  to  Rodman's  exposition  of  it,  precedent  to  his  endeavor 
to  apply  it  in  a  cast  gun.  Chambers'  patent  of  1840  is  especially 
worthy  of  note,  in  that  it  embodies — 

First.  The  slotted  screw  breech  fermeture. 

Second.  The  hinged  movement  of  the  breech  mechanism,  when 
withdrawn  to  clear  the  way  for  loading  through  the  breech. 

Third.  The  loading  tray  or  sleeve  inserted  in  the  breech  to  cover 
the  threads  in  loading. 

Fourth.  The  biconical  shape  given  to  the  shrinkage  surfaces  of  the 
hoops  to  afford  longitudinal  strength. 

In  design  this  gun  was  a  wrought-iron  breech-loading  smoothbore, 
built  up  with  a  tube  extending  in  one  piece  from  breech  to  muzzle, 
and  incased  with  several  layers  of  hoops,  shrunk  on.  The  principle 
of  initial  tension  is  not  enunciated  in  the  design,  but  it  was  provided 
that  the  rings  should  be  put  on  at  a  heat  sufficiently  low  to  prevent 
oxidation.  We  find  the  slotted  screw,  the  hinge  movement  of  the 
breech  mechanism,  and  the  loading  tray  in  the  perfected  system  now 
designated  the  French  breech  mechanism.     The  biconical  shape  of 


14  GUN    MAKING    IN    THE    UNITED   STATES. 

hoops  is  an  idea  not  long  since  introduced  in  the  De  Bange  guns, 
but  its  utility  is  doubtful.  As  regards  the  Broadwell  ring  used  in 
the  Krupp  gun,  it  appears  to  have  been  derived  from  a  patent  taken 
out  by  Broadwell  in  Russia.  Broadwell's  patent  was  placed  first  in 
Russia  in  1861,  second  in  England  in  1864,  and  third  in  the  United 
States  in  1866. 

INITIAL  TENSION   IN   CAST-IRON   GUNS. 

The  great  improvement  in  the  manufacture  of  cast-iron  smooth- 
bore guns  was  due  to  the  introduction  of  Rodman's  method  of  casting, 
by  cooling  from  the  interior,  coupled  with  the  well-conditioned  out- 
side lines  which  he  adopted  for  his  gun.  Major  Wade's  report  of 
August  4,  1849,  contains  an  account  of  the  trial  of  the  first  gun  made 
on  this  plan.  Two  8-inch  Columbiads  were  cast  at  the  same  time 
from  the  same  metal.  One  was  cast  solid  in  the  usual  manner  and 
the  other  according  to  the  Rodman  plan.  The  first  was  burst  at  the 
eighty-fifth  round,  while  the  second  endured  251  rounds.  An  equal 
and  even  greater  degree  of  superiority'  was  evinced  in  the  succeeding 
trials  of  8  and  10  inch  guns  made  in  1851.  The  object  sought  to  be 
attained  by  Rodman  finds  application  to-day  in  what  Ave  consider 
the  highest  principles  of  gun  construction.  Following  the  discussion 
of  the  action  of  a  central  force  as  enunciated  by  BarloAv  some  years 
previousl3%  Rodman,  in  1851,  pointed  out  not  only  the  injurious 
effect  of  exterior  cooling  as  causing  a  zone  of  metal  near  the  exterior 
to  remain  in  a  state  of  compression  and  thus  actually  assist  in  the 
rupture  of  the  gun,  but  also  showed  that  the  effect  of  cooling  from  the 
interior  would  be  to  so  dispose  the  metal  that  in  resisting  an  interior 
pressure  each  concentric  laminae  of  metal  throughout  the  wall  might 
be  equally  strained  to  its  limit  to  resist  tangential  rupture.  To  use 
his  own  words,  referring  to  a  gun  which  had  withstood  1.500  rounds 
without  bursting:  "The  object  of  my  improvement  was  in  part,  if 
not  fully,  attained,  viz,  to  throw  the  gini  upon  a  strain  such  that 
*  *  *  each  one  of  the  indefinitely  thin  cylinders  composing  the 
thickness  of  the  gun  shall  be  brought  to  the  breaking  strain  at  the 
same  instanty  Evident!}^  a  condition  like  this  would  give  a  maxi- 
mum resistance,  since  it  would  be  determined  by  the  product  of  the 
mean  strain  of  the  laminae  into  the  thickness  of  the  wall,  and  if  each 
lamina^  worked  to  its  limit  that  product  would  be  the  greatest 
possible. 

But  while  we  may  not  deny  the  utility  of  the  Rodman  process  as  a 
Avhole,  it  Avas.  and  must  continue  to  be,  uncertain  in  its  operation,  inde- 
pendent of  the  always  existing  uncertainty  about  the  soundness  of  the 
castings.  A  number  of  cases  are  knoAvn  in  which  the  castings  burst 
spontaneously  on  cooling,  and  in  some  cases  after  being  put  in  the 
lathe  for  finishing.    And  we  know  also  that  a  frequent  cause  for  rejec- 


GUN    MAKING    IN    THE    UNITED    STATES.  15 

tion  of  these  guns  was  the  existence  of  cavities  uncovered  in  the  bor- 
ing. The  plan  may  be  expected  to  do  more  than  counteract  the  effect 
of  the  hurtful  strains  arising  from  cooling  solid  castings  in  the  usual 
manner;  it  will,  in  fact,  produce  to  an  uncertain  extent,  however,  the 
proper  direction  of  initial  strains.  It  would  be  the  merest  accident 
should  there  be  brought  about  the  perfect  state  indicated  by  the  theory. 
Nor  was  this  to  be  exj^ected,  since  the  question  of  the  proper  degree  of 
temperature  to  be  maintained  at  the  exterior  and  the  rate  of  cooling 
from  the  interior  was  investigated  only  in  a  crude  manner.  A  little 
studv  of  the  problem  will  show  that  in  order  to  produce  an  accurate 
degree  of  tension  in  the  indefinitely  thin  cylinders  composing  the 
thickness  of  the  wall  the  most  delicate  appliances  would  be  necessary ; 
the  exterior  should  remain  heated  to  the  very  last  and  the  cooling  pro- 
gress regularly,  according  to  a  certain  fixed  law,  from  the  interior. 
Again,  it  is  impossible  to  maintain  the  heat  of  fusion  at  the  exterior 
sufficiently  long  for  this  process  to  be  accomplished,  so  that  the  metal 
there  becomes  set  and  prevents  a  zone  of  adjacent  metal  within  from 
contracting  as  it  should  upon  the  interior  mass.  These  are  not  theo- 
retical ideas;  they  are  the  results  of  carefid  investigations.  The 
method  adopted  for  determining  the  amount  of  tension  in  the  castings 
was  to  cut  off  a  thin  cross  section  of  the  gun  to  form  the  "  initial  ten- 
sion "  ring,  and  then  slot  this  ring  through  on  one  side  along  a  radius, 
the  separation  of  the  ring  measured  in  the  slot  at  the  outer  circumfer- 
ence being  taken  as  a  measure  of  the  tension.  To  what  extent  this 
method  gives  a  true  measure  of  the  initial  tension  strains  is  entirely 
problematical  and  unknown ;  it  can  be  said  only  to  show  the  aggregate 
result  of  the  interior  strains  of  every  sort  existing  in  the  castings,  and 
either  localized  or  general.  In  theory,  it  was  desired  to  reach  an  ini- 
tial tension  of  about  20,000  pounds,  or  two-thirds  (66  per  cent)  of  the 
average  resistance  of  the  cast  iron.  In  practice,  how^ever,  it  was  found 
that  the  initial  tension  of  the  10-inch  guns  varied  from  3,000  to  28,000, 
or  from  12  to  72  per  cent  of  the  actual  tenacity  of  the  iron,  and  the  15- 
inch  guns  from  4,000  to  25,000,  or  from  15  to  61  per  cent  of  the  actual 
tenacity.  These  results  combine  two  equally  important  and  unknown 
factors,  viz,  the  uncertainty  of  the  method  to  produce  the  results 
desired,  and  the  inadequacy  of  the  method  used  for  determining  the 
initial  tension.  Investigations  and  extended  attempts  to  introduce  the 
Rodman  method  of  casting  have  been  made  in  Russia  and  proved 
unsatisfactory,  because  it  was  found,  upon  careful  investigation,  that, 
the  desired  state  of  initial  tension  could  not  be  produced  with  any 
degree  of  certainty.'* 

The  results  of  an  important  investigation  recently  made  at  Water- 
town  Arsenal  in  this  matter  are  given  in  Notes  on  the  Construction  of 

a  Notes  on  the  Construction  of  Ordnance,  No.  21,  p.  7. 


16 


GUN    MAKING    IN    THE    UNITED   STATES. 


Ordnance  No.  38,  by  Lieut.  William  Crozier,  Ordnance  Department, 
U.  S.  Army.  "  To  determine  the  form  of  the  initial  tension  curve  and 
the  value  of  its  ordinates,  a  ring  (section)  was  cut  from  the  portion  of 
the  sinking  head  of  the  gun  immediateh'  adjoining  that  from  which 
the  trial  cylinder  was  taken.  This  ring  was  scored  with  concentric 
circles  about  1  inch  apart,  whose  diameters  were  measured.  It  was 
then  finshed  to  the  radial  dimensions  of  the  trial  cylinder  and  the 
diameters  of  the  circles  again  measured.  In  this  state  it  had  the  initial 
condition  of  the  trial  cylinder."  It  was  then  cut  into  concentric  rings, 
a  little  less  than  1  inch  in  thickness,  by  cutting  midway  between  the 
scored  circles,  after  which  the  diameters  of  the  circles  were  a  third 
time  measured — the  changes  of  dimensions  indicating  the  amount  and 
character  of  the  strains  to  which  the  small  rings  were  subjected  before 
being  detached.  The  dimensions  were  measured  with  great  care  on 
four  different  diameters,  making  equal  angles  with  each  other." 

The  results  of  the  measurements  thus  made  are  shown  in  the  follow- 
ing figures : 

Scale  of  Tension. 
Scale  of  Tension. 

.05=1000  lbs. 
.05=1000  lbs. 


10         6 

5          to 

Axis  C 

f  bore. 

^\: 

1st  Circle  2 

^\ 

2nd      ••      S 

\ 

3rd       ••      1 

.  ■   "          a. 

\         4th       ■•     "> 

1        5th       •■     ^ 

■ 

.  \      sth      ■■    § 

7th       ■■      o 

a 

..    ..8th       ■■     & 

■ 

5 

9th    V  •'      ■ 

■ 

J.'   .  lOth   ■■-  •• 

:  .^^^^__^^^_^^ 

/r 

.  .1.1 2th 

^ 

The  expansion  of  the  thin  rings  on  being  released  gave  a  measure 
of  the  compression  to  which  each  had  l)een  subjected  in  the  casting, 
and  the  contraction  of  others  showed  their  state  of  extension  in  the 
casting.  The  platted  curves  show  that  the  interior  of  the  casting 
was  compressed  as  designed  in  the  Rodman  process,  but  the  exterior 
was  in  a  state  of  irregular  tension.    The  highest  state  of  extension  is 


o  Referring  to  the  core  of  an  experimental  wire-wound  gun  cylinder. 


GUN    MAKING    IN    THE   UNITED    STATES.  17 

about  one-fifth  the  thickness  from  the  exterior,  and  the  exterior  metal 
itself  was  in  a  state  of  compression — thus  producing  a  strain  in  that 
place  which  would  tend  to  assist  an  interior  (powder)  pressure  in 
bursting  the  gun.  This  metliod  of  investigation  is  evidently  best 
suited  to  elucidate  the  efficacy  of  the  so-called  "  natural  hooping " 
involved  in  the  Eodman  process.  The  detached  rings  were  made  as 
thin  as  could  be  manipulated  with  due  regard  to  accuracy  of  results, 
and  a  good  degree  of  approximation  was  made  to  separating  the  sec- 
tion into  the  indefinitely  thin  cylinders  of  which  the  wall  is  conceived 
to  be  composed.  The  action  of  these  thin  cylinders,  on  being  detached 
from  the  section,  indicated  their  state  of  strain  in  the  casting  and 
gave  a  measure  of  the  efficacy  of  the  natural  hooping — it  being  con- 
sidered that  the  rings  became  practically  neutral,  regarding  tangential 
strains,  on  being  detached.  At  a  subsequent  period  these  thin  rings 
were  cut  in  two  on  one  side  in  a  similar  manner  to  the  ordinary  test 
of  an  initial  tension  ring  or  full  section  of  a  gun.  Their  behavior  was 
very  irregular,  and  gave  no  indication  of  the  initial  tension  shown 
by  the  preceding  experiment  to  have  existed  in  the  wall  of  the  casting. 
This  behavior  of  the  thin  rings,  on  being  cut  apart,  indicated  the 
existence  of  local  strains  of  an  uncertain  character,  and  showed  the 
unreliability  of  the  initial  tension  test  as  usually  followed.  I  have 
devoted  the  more  space  to  this  subject  of  initial  tension  than  might 
otherwise  be  considered  necessary,  because  of  its  bearing  upon  the 
question  of  steel-cast  or  other  guns  now  advocated  to  be  made  after 
this  process. 

CAST-IRON  SMOOTHBOKE  GUNS  IN  SERVICE. 

The  number  of  Rodman  smoothbore  guns  now  available  for  the 
land  service  is  210  8-inch,  998  10-inch,  305  15-inch,  and  2  20-inch. 
These  guns,  if  properly  mounted,  can  be  expected  to  perform  efficient 
service  in  case  of  necessity.  For  armor  piercing,  the  8  and  10  inch 
would  be  of  little  value.  The  powder  charge  of  the  10-inch  is  25 
pounds  of  mammoth  powder  and  the  round  projectile  weighs  128 
pounds,  giving  a  muzzle  energy  of  2,000  foot-tons,  which,  however,  for 
this  form  of  projectile,  would  fall  away  very  rapidly.  But  these  guns 
may  be  made  useful  in  the  defense  of  minor  points  and  torpedo  lines. 
The  15-inch  gun  fires  a  projectile  weighing  450  pounds,  and  through 
the  experiments  made  by  the  Ordnance  Board  at  Sandy  Hook  in 
1883  its  powder  charge  has  been  increased  to  130  pounds  of  hexagonal 
powder,  which  gives  an  average  pressure  of  about  25,000  pounds  per 
square  inch  in  the  bore.  With  this  charge  the  range  at  20°  elevation 
is  3.75  miles.  At  the  same  time  it  was  found  that  the  projectile  would 
pierce  10  inches  of  iron  at  1,000  yards.  The  initial  velocity  of  1,700 
f.  s.  imparts  a  muzzle  energy  of  9,000  foot-tons,  but  so  rapidly  would 
7733—08 2 


18  GUN    MAKING    IN   THE    UNITED   STATES, 

this  fall  oflf  that  at  1,000  j'ards  the  energy  would  be  considerably  less 
than  that  of  the  projectile  of  the  new  8-inch  steel  rifle,  which  starts 
with  an  energy  of  7,200  foot-tons. 

PARROTT   RIFLES. 

Although  all  the  Parrott  guns  are  now  classed  as  "  retained  cali- 
bers "  in  the  service — that  is,  only  to  be  used  in  cases  of  necessity — 
they  performed  a  most  important  duty  in  our  civil  war,  and  are 
especially  worthy  of  mention  as  being  the  first  extended  system  of 
rifled  guns  introduced  in  the  United  States.  Their  founder  and 
]naker  will  always  be  regarded  as  one  of  our  most  successful  gun 
makers,  and  remembered  as  a  man  distinguished  in  the  art.  He  made 
a  wide  reputation  for  himself  and  for  the  West  Point  Foundry,  at 
Cold  Spring,  N.  Y.,  which,  under  his  successors,  has  continued-  to 
afford  indispensable  aid  to  the  Government  in  the  production  of  new 
types  of  guns,  and  has  materially  assisted  in  maintaining  and  diffus- 
ing a  knowledge  of  gun  making  in  the  country.  My  personal  obli- 
gations in  this  respect  are  deep,  for  it  has  been  my  good  fortune  to 
have  remained  on  duty  there  as  an  inspector  for  nearly  six  3'ears, 
with  opportunities  for  acquiring  the  practical  knowledge  that  abounds 
at  the  foundry. 

The  history  of  the  Parrott  guns  is  so  well  known  that  it  will  be 
necessary  to  call  attention  only  to  certain  features.  The  smaller  cali- 
bers showed  in  some  cases  a  remarkable  endurance  in  war  service,  and 
the  same  was  true  to  a  less  extent  with  the  larger  calibers,  but  failures 
of  the  100,  200,  and  300  pounders  were  relatively  numerous.  Several 
instances  which  have  occurred  in  practice  firing  with  these  guns  in 
recent  years  have  also,  in  connection  with  modern  improvements  in 
construction,  led  to  the  obvious  necessity  of  retiring  them  from  service 
as  soon  as  they  can  be  replaced.  The  uncertainty  in  endurance  of  the 
heavier  calibers  must  be  regarded  as  evidence  of  the  unsuitability  of 
cast-iron  as  a  metal  for  making  heavy  rifled  guns.  Any  system  of 
conversion  for  these  guns  would  necessitate  an  enlargement  of  the 
bore,  and  corresponding  thinning  down  of  the  already  weak  walls; 
moreover,  the  guns  were  made  for  quick  burning  powder  and  are  too 
short  to  realize  a  proper  effect  with  slower  burning  powders.  The 
wrought  iron  reenforce  band  of  these  guns  was  made  from  a  bar  coiled 
and  welded  in  the  form  of  a  hollow  cylinder,  which  was  afterwards 
finished  for  shrinkage.  The  effect  of  this  was  to  dispose  the  fibers  of 
the  iron  to  resist  tangential  rupture,  and  the  band  was  probably  not 
expected  to  afford  any  resistance  to  longitudinal  rupture.  The  cast- 
iron  wall  of  the  100-pound  rifle,  for  instance,  is  one  caliber  (nearly) 
in  thickness,  and  the  thickness  of  the  reenforce  band  is  one-half  cali- 
ber (3.2  inches).     The  shrinkage  prescribed  for  the  band  was  one- 


GUN    MAKING   IN    THE    UNITED    STATES.  19 

sixteenth  of  an  inch  to  the  foot,  or  0.0052  of  an  inch  per  linear  inch. 
This  is  fully  four  times  as  much  as  would  now  be  regarded  a  useful 
limit  for  the  shrinkage  of  a  wrought-iron  gun  hoop;  however,  these 
bands  were  assembled  at  a  high  heat  and  the  iron  band  was  allowed 
to  adjust  itself  without  exterior  cooling;  hence  we  do  not  find  in 
these  guns  an  example  of  the  practice  of  hooping,  as  now  understood. 
And  the  excessive  shrinkage  of  the  single  band,  by  producing  un- 
duly heavy  cross  strains  in  the  section  of  the  cast-iron  at  the  front, 
tends  to  weaken  the  gun  to  resist  longitudinal  rupture,  as  may  be 
inferred  from  the  manner  in  which  a  good  proportion  of  the  fail- 
ures have  taken  place. 


11. 

Period  fro3i   1872  to  1881 — Hitchcock,  Mann,  Lyman-Haskell, 

AND     WOODBRIDGE     GuNS — CoN\T:RTED     MuzZLE-LoaDING     RiFLES — 

Converted   Breech-Loading   Rifles — Sutcliffe  and   Thompson 
Guns — Field  Guns. 

The  Heavy  Gun  Board  of  1872  was  appointed  to  meet  in  New 
York  City  for  the  purpose  of  examining  such  models  of  heavy  ord- 
nance as  might  be  presented  to  it,  and  of  designating  and  reporting 
to  the  Chief  of  Ordnance  such  models  as  might  be  selected  for  ex- 
periment. Colonel  'WTiitely,  of  the  Ordnance  Department,  was 
president  of  the  board,  and  there  were  besides  one  officer  of  Engi- 
neers, two  of  Ordnance,  and  two  of  Artillery  as  members.  A  spe- 
cial appropriation  was  made  in  advance  by  Congress  for  the  pur- 
pose of  carrving  out  the  recommendations  of  the  board.  The  board 
examined  into  40  inventions  and  proposals,  and  selected  the  9  follow- 
ing, arranged  in  the  order  of  merit  determined  by  the  board,  viz : 

Muzzle-loading  guns : 

1.  Dr.   W,   E.  Woodbridge. 

2.  Alonzo  Hitchcock's. 

3.  Cast-iron  guns,  lined  with  wrought-iron  or  steel  tubes. 

Breech-loading  guns: 

1.  Friedrich  Krupp. 

2.  E.  A.  Sutcliffe. 

3.  Nathan  Thompson. 

4.  French  and  Swedish  system. 

Miscellaneous : 

1.  H.  F.  Mann's. 

2.  Lyman's  multicharge. 

The  Ordnance  Department  was  occupied  in  the  ten  years  following, 
pursuant  to  enactments  of  Congress,  in  the  construction  and  trial 
of  the  guns  recommended  by  this  board.  The  Krupp  gun  was  in- 
tended to  be  tested  for  a  trial  of  the  breech  mechanism  as  well  as 
the  system  of  construction.  However,  no  gun  of  Krupp's  system 
was  procured,  for  the  reason  the  War  Department  was  unable  to 
comply  with  his  conditions,  which  necessitated  the  purchase  of  a 
number  of  guns  in  case  the  trial  gun  should  prove  a  success.  Such 
an  agreement  by  the  AVar  Department  could  only  have  been  made 
20 


GUN   MAKING   IN    THE    UNITED    STATES.  21 

in  case  Congress  had  already  appropriated  the  money  for  the  pur- 
pose, and  this  was  not  done.  But  the  Krupp  breech  mechanism 
was  subsequently  tried  in  combination  with  the  converted  wrought- 
iron  lined  guns  recommended  by  the  board,  after  the  muzzle-loading 
guns  of  the  same  type  had  been  successfully  tested. 

The  Hitchcock  gun  proposed  was  a  9-inch  muzzle-loading  rifle, 
to  be  made  by  welding  together  disks  or  "  cheeses  "  of  wrought  iron 
forming  sections  of  the  gun  to  make  a  solid  wrought-iron  piece. 
The  work  was  conducted  at  the  Springfield  Armory  under  the 
direct  supervision  of  the  inventor.  After  nearly  three  years'  labor 
and  the  expenditure  of  a  large  amount  of  money  the  project  was 
abandoned  as  being  too  difficult  and  costly,  if  not  impracticable, 
to  be  fulfilled. 

No  provision  was  made  in  this  j)eriod  for  a  trial  of  the  French 
and  Swedish  system.  The  Mann  gim  considered  by  the  board  was 
an  8-inch  breech-loading  rifle  already  in  possession  of  the  Ordnance 
Department,  which  had  already  been  fired  about  50  rounds.  Some 
alterations  were  made,  and  the  gun  was  fired  11  rounds  at  Sandy 
Hook  in  1875,  after  which  it  was  moved  to  Philadelphia  to  be  placed 
on  exhibition  at  the  Centennial.  The  Lyman's  multicharge  gim 
in  existence  at  this  time  was  a  6-inch  breech-loading  rifle,  designated 
by  its  private  owners  as  the  "  Multicharge  100-pounder  rifle  gun." 
But  since  improved  models  of  both  the  Mann  and  Lyman-Haskell 
guns  were  tested  at  a  period  subsequent  to  this,  further  references 
will  be  deferred  to  an  account  of  those  trials. 

WOODBRIDGE   10-INCH   WIRE-WOUND   GUN. 

It  appears  from  the  record  that  Doctor  Woodbridge  first  presented 
a  plan  for  a  wire-wound  gun  to  the  War  Department  July  30,  1850, 
which  establishes  his  claim  to  priority  in  the  idea.  A  2.5-inch  gun, 
constructed  upon  his  plans  at  the  Washington  Navy- Yard,  was 
tested  for  endurance  at  the  Springfield  Armory,  where,  in  1865, 
Major  Laidley  reported  that  1,327  rounds  had  been  fired  from 
it  and  the  firing  had  been  stopped  because  the  trunnion  band  broke 
loose,  but  the  gun  itself  was  practically  uninjured.  The  trial  gun 
decided  upon  in  1872  was  a  muzzle-loading  rifle  of  10-inch  caliber. 
It  consisted  of  a  thin  steel  tube  strengthened  by  wire  wound  on  its 
exterior  surface,  tube  and  wire  being  subsequently  consolidated 
into  one  mass  by  a  brazing  solder  melted  into  the  interstices.  The 
tube  extended  through  from  breech  to  muzzle,  was  left  solid  for  a 
length  of  19  inches  to  form  the  breech,  and  had  a  thickness  of  1.5 
inches  around  the  bore.  The  length  of  the  bore  was  155  inches,  or 
15.5  calibers.     The  following  brief  description   of  the  process  of 


22  GUN   MAKING   IN   THE   UNITED  STATES. 

manufacture  is  taken  from  reoort  of  Captain  Prince,  dated  March 
31,1875: 

Square  wire  is  wound  upon  a  steel  core  somewhat  larger  than  the  intended 
bore  of  the  gun,  a  sufficient  number  of  wires  being  wound  at  once,  side  by  side, 
to  produce  the  required  obliquity  of  the  turns.  The  successive  layers  have 
opposite  twist,  their  number  being,  of  course,  sufficient  to  give  the  desired 
exterior  diameter  to  the  gun.  When  thus  wound,  the  whole  mass  is  inclosed 
in  a  tight  case,  to  protect  it  from  oxidation,  and  is  heated  therein  to  a  tem- 
perature somewhat  above  that  required  for  the  fusion  of  the  metal  to  be  used 
for  consolidating  it.  The  soldering  metal  is  then  run  in,  filling  all  the  inter- 
stices of  the  mass.  When  properly  cooled,  the  gun  is  bored  and  finished  from 
the  mass  in  much  the  same  way  as  if  it  were  a  common  casting. 

The  construction  of  the  gun  was  undertaken  at  Frankford  Arsenal 
in  October,  1872,  and  after  many  delays  and  difficulties  was  com- 
pleted in  April,  1876.  It  was  fired  10  rounds  at  Frankford  Arsenal 
with  powder  charges  increasing  from  40  to  70  pounds,  and  pro- 
jectiles from  343  to  397  pounds.  In  these  firings  imperfect  brazing 
was  developed  and  a  crack  was  started  on  the  exterior  of  the  gim. 
The  same  gun  was  taken  up  in  1881  and  fired  for  endurance  under 
the  supervision  of  the  board  on  heavy  ordnance  and  projectiles. 
The  charge  principally  used  was  70  pounds  hexagonal  powder  and 
395-pound  projectile.  With  a  charge  of  80  pounds  of  powder  the 
gun  parted  longitudinally  after  a  total  of  93  rounds,  the  "  fracture 
being  26.75  inches  from  bottom  of  bore  in  the  plane  of  openings 
noted  and  measured  during  the  firing?"  Notwithstanding  the  poor 
success  of  this  gun,  as  shown  in  the  difficulties  attending  its  manu- 
facture, and  its  subsequent  failure  under  proof,  the  Getty  Board, 
being  much  impressed  with  the  utility  of  continued  experiments 
with  wire  gims,  recommended  that  a  breech-loading  gun  of  the  same 
construction  be  made  and  tried,  with  others  of  different  designs 
presented  by  Doctor  Woodbridge.  These  later  designs  apparently 
possess  more  merit  and  have  superseded  the  first  construction  in 
which  the  brazing  of  the  wire  formed  almost  the  sole  reliance  for 
longitudinal  strength.  The  recommendation  to  try  another  brazed 
wire  gun  has  never  been  carried  out. 

CONVERTED    MUZZLE-LOADING    RIFLES. 

These  gims  consist  essentially  of  a  cast-iron  body  or  casing, 
strengthened  with  a  wrought-iron  or  steel  rifled  tube  which  has  a 
thickness  of  wall,  over  the  seat  of  charge,  equal  to  about  one-third 
the  caliber  of  the  gun.  Thej^  constitute  a  system  of  built-up  guns, 
in  which  the  shrinkage  of  the  casing  on  the  tube;  is  negative,  or  there 
is  a  pla3^  The  casing,  except  in  a  single  gun  of  new  construction — 
the  12:^-inch  rifle — is  formed  of  the  Rodman  smoothbore  gun,  from 
which  about  fifteen  one-himdredths  of  the  caliber  only  in  thickness  of 
cast  iron  is  removed  to  enlarge  the  bore  for  the  reception  of  the  com- 


GUN    MAKING   IN    THE   UNITED    STATES.  23 

paratively  thick  tube  of  reduced  bore.  In  the  wrought-iron  tubes 
formed  by  coiling  and  welding  bars  of  the  very  best  grade  of  wrought 
iron,  the  fiber  is  arranged  to  resist  directly  the  dangerous  tangential 
strain,  and  these  tubes  are,  besides,  reenforced  dver  the  seat  of  the 
charge  by  a  sleeve  or  jacket  of  wrought  iron,  similarly  formed 
and  shrunk  over.  These  wrought-iron  tubes  would  alone  support 
an  interior  pressure  of  13,000  pounds  per  square  inch,  or  more  than 
one-third  of  the  whole  pressure  that  the  guns  are  called  upon  to  bear. 
Even  supposing  the  tube  inert,  its  interposition  causes  a  reduction 
of  about  31  per  cent  of  the  pressure  in  the  bore  in  transmission  to 
the  cast  iron,  because  the  pressure  upon  1  square  inch  of  the  bore 
would  be  distributed  upon  1.7  square  inches  of  the  interior  of  the 
outside  cast-iron  body.  In  the  later  constructions  where  steel  is  used, 
the  metal  is  a  fine  quality  of  highly  ductile  steel  suited  to  the  con- 
struction, and  the  tube  in  itself  is  able  to  safely  support  an  interior 
pressure  of  18,000  pounds  per  square  inch,  or  about  one-half  of  the 
whole  strain  upon  the  gun  when  fired. 

In  mode  of  conversion,  these  guns  are  divided  into  three  classes, 
viz:  (1)  The  muzzle  insertion  with  wrought-iron  tube;  (2)  th© 
breech  insertion  with  wrought-iron  tube:  (3)  the  muzzle  insertion 
with  steel  tube. 

The  difference  between  the  plans  of  muzzle  and  breech  insertion 
lies  principally  in  this:  In  the  former  the  tube  is  supported  longi- 
tudinally from  a  force  that  would  tend  to  open  coil  welds  by  the 
muzzle  screw  collar;  while  in  the  latter,  there  are  several  shoulders 
on  the  outside  of  the  tube  which  bear  against  corresponding  shoulders 
in  the  casing,  and  the  tube  by  this  means  is  well  supported  longitu- 
dinally from  movement  forward  at  several  distances  throughout  its 
length.  A  special  importance  attaches  to  this  in  the  use  of  coil- 
welded  tubes,  which  are  more  apt  to  develop  a  weakness  at  the  coil- 
weld  joints  than  in  an}-  other  part. 

These  guns  were  proposed  as  an  expedient  for  converting  the 
comparatively  useless  10-inch  smoothbores  into  rifled  guns  to  meet 
the  increasing  thickness  of  armor  carried  by  vessels.  "Wlien  this 
system  was  inaugurated  the  8-inch  caliber  was  seen  to  be  a  gun  that 
would  equal  in  power  the  existing  English  guns  of  like  caliber,  and 
it  was  hoped  that  the  extension  of  the  system  to  guns  of  larger  cali- 
ber, would  prove  a  success.  As  an  additional  reason  for  the  adoption 
of  the  system,  our  forts  were,  and  still  remain,,  constructed  with 
casemates  adapted  to  accommodate  a  gun  of  about  the  dimensions 
of  the  10-inch  Rodman,  and  the  conversion  of  this  gun  into  a  rifle 
afforded  at  that  time,  the  best  and  the  only  available  means  for  in- 
creasing the  efficiency  of  the  casemated  forts  to  a  maximum.  At  the 
same  time,  however,  the  Chief  of  Ordnance,  General  Benet,  then 


24  GUN    MAKING    IN    THE    UNITED   STATES. 

placed  himself  upon  record  as  saying : «  "  There  is  little  doubt  that 
steel  is  the  best  material  for  guns."  He  did  not  recommend  an  ex- 
penditure of  a  large  amount  of  money  for  a  gun  plant  to  make  the 
proposed  conversion,  but  drew  attention  to  the  success  of  the  tubing, 
as  enabling  the  smoothbore  guns  to  be  made  strong  enough  for  use  as 
rifles  and  recommended  the  system  as  an  "  easy  and  economical  mode 
of  converting  our  cheap  cast-iron  smoothbores  into  powerful  and 
efficient  rifles." 

The  lining  of  a  cast-iron  body  with  a  steel  tube,  as  a  system  of 
construction  for  rifled  guns  (10-inch  and  12-inch),  was  recommended 
for  trial  by  the  Ordnance  Board,  convened  under  the  order  of  the 
War  Department,  dated  December  16,  1867.  The  matter  was  brought 
to  the  attention  of  the  board  of  1872  by  Major  Crispin,  and  this 
board  recommended  the  conversion  of  four  10-inch  Rodman-  gams 
upon  the  plans  proposed,  which  were  modeled  upon  the  Palliser  plan 
of  muzzle  insertion,  then  successfully  established  in  England,  and 
the  Parsons  (American)  plan  of  breech  insertion.  The  details  of  the 
construction  of  the  guns  were  subsequently  arranged  by  boards  of 
ordnance  officers,  convened  September  18,  1872,  and  October  10,  1874. 
It  Avas  decided  that  two  of  the  four  experimental  guns  be  made  of 
8-inch  caliber  and  two  of  9-inch  caliber,  one  of  each  to  be  tubed  from 
the  front,  and  one  from  the  rear;  the  muzzle  insertion  to  be  wrought- 
iron  tubes  and  the  breech  insertions  jacketed  steel  tubes. 

The  wrought-iron  tubes  were  procured  from  Armstrong  and  the 
parts  of  the  steel  tubes  from  the  Bochum  Steel  Company,  Germany. 
The  8-inch  gun,  with  wrought-iron  tube  inserted  from  the  muzzle, 
was  at  once  established  as  a  success.  The  9-inch  gun,  of  the  same 
model,  was  also  successfully  proved  by  firing  502  rounds,  but  this 
caliber  made  the  gun  too  light  to  com'pete  successfully  with  foreign 
guns  of  like  caliber.  The  8-inch  gun,  with  steel- jacketed  tube  inserted 
from  the  rear,  Avas  burst  after  firing  456  rounds,  of  which  286  were 
fired  after  the  development  of  a  crack  in  the  steel  tube  at  the  one 
hundred  and  seventy-fifth  round.  The  9-inch  gun,  of  the  same 
model,  was  not  fired  to  extremity.  The  steel  procured  for  these 
tubes  was  not  of  the  uniform  strength  considered  desirable,  and  its 
elastic  limit  was  Avhat  we  would  now  consider  exceedingly  low — that 
was  from  23,000  to  25,000  pounds  per  square  inch.  Following  the 
success  of  the  8-inch  muzzle  insertion  with  wrought-iron  tube  a 
gun  of  10- inch  caliber,  converted  from  a  13-inch  smoothbore,  and  also 
a  new  construction — the  12.25-inch  rifle — Avere  made  upon  the  muzzle- 
insertion  plan.  The  12.25  inch  was  made  18.5  calibers  in  length  of 
bore  and  was,  when  made,  one  of  the  most  powerful  guns  of  that 
caliber  in  existence.  The  trials  of  these  guns  of  larger  caliber  devel- 
oped the  unsuitability  of  the  muzzle-insertion  plan  when  applied  to 

o  Report  of  the  Chief  of  Ordnance,  1875,  p.  94. 


GUN    MAKING   IN    THE    UNITED    STATES.  25 

them,  owing  to  defects  developed  in  the  coiled  welded  tubes  which, 
in  this  plan  of  conversion,  received  longitudinal  support  only  from 
the  muzzle  screw  collar.  In  the  proof  of  the  10-inch  gun  the  tube 
was  torn  apart  longitudinally,  after  a  few  rounds,  and  a  large  por- 
tion of  the  muzzle  end  of  the  tube  was  projected  forward  out  of  the 
gim.  The  tube  was  repaired,  and  the  gun  afterwards  fired  some 
thirty  rounds.  This  led  to  the  substitution  of  the  breech-insertion 
plan  as  essential  to  the  construction  of  guns  of  larger  caliber  than 
8  inches.  And  by  analogy  the  same  reasoning  led  to  the  relinquish- 
ment of  the  muzzle  insertion  for  8-inch  guns.  Experimental  guns 
of  8  and  11  inch  caliber  were  made  on  the  breech-insertion  plan  and 
proved  for  endurance.  Only  a  few  of  the  11  inch  were  made,  as  this 
construction  gave  place  to  the  11-inch  converted  breech-loaders. 
Thus  it  came  about  that  the  8-inch  gun  was  the  only  caliber  of  these 
converted  muzzle-loading  rifles  which  was  adopted  and  manufac- 
tured for  issue  in  service. 

The  wrought-iron  tubes  for  the  first  two  experimental  guns  were, 
as  already  mentioned,  procured  from  England,  but  the  third  was 
procured  from  "West  Point  Foundry,  and  the  manufacture  of  these 
tubes  became,  at  a  later  period,  a  regular  product  of  home  produc- 
tion. So  also  with  the  bar  iron  for  making  the  tubes.  The  demand 
for  this  production  at  home  soon  led  to  its  procurement  in  the  quan- 
tity desired  and  in  quality  fully  equal  to  foreign  make.  This  iron 
was  manufactured  at  the  Ulster  Iron  Works,  Saugerties,  N.  Y.  The 
work  of  conversion  was  done  at  the  West  Point  and  South  Boston 
foundries. 

The  use  of  a  steel  tube,  muzzle  insertion,  was  introduced  in  the 
50  guns  last  converted.  At  this  time  (1883)  it  had  become  apparent 
not  only  that  steel  was  the  best  material  for  guns,  but  also  that 
improvements  in  the  manufacture  of  gun  steel  in  other  countries 
had  removed  the  doubts  raised  by  our  own  trials  of  inferior  metal. 
It  therefore  became  a  highly  important  matter  to  encourage  the  pro- 
duction of  gain  steel  at  home.  It  was  found  also  that  the  steel-tube 
conversion  could  be  made  at  a  considerably  less  cost  than  the 
wrought  iron.  With  these  ends  in  view,  an  experimental  gun  was 
first  made  and  satisfactorily  proved  for  endurance.  The  order  for 
50  tubes  was  then  placed  with  the  Midvale  Steel  Works  and  suc- 
cessfully filled.  This  was  the  largest  order  for  steel  forgings  that 
had  up  to  that  time  been  placed  in  the  United  States.  A  special 
fine  quality  of  steel  was  demanded,  possessing  great  ductibility,  com- 
bined with  a  relatively  low  elasticity  and  tenacity,  and  the  fulfill- 
ment of  the  order  did  much  to  advance  the  manufacture  of  gun 
steel  in  this  country,  and  as  well  to  increase  the  experience  of  the 
Midvale  Steel  Company  and  to  establish  the  excellent  reputation  for 
the  manufacture  of  gun  steel  which  that  company  now  holds. 


26 


GUN    MAKING    IN    THE    UNITED   STATES. 


Five  hundred  rounds  was  fixed  as  the  number  necessary  to  prove 
the  endurance  of  the  8-inch  guns.  The  following  table  gives  a  list 
of  the  type  or  experimental  gims  fired  and  the  number  of  rounds 
fired  from  each : 


Endurance  of  experimental  converted  muzzle-loading  rifles,  dating  from  187^. 


Average 

A-serage 

Num- 
of 

Nature  of  gnn. 

weight 
of 

weight 
of  pro- 

rounds 

Condition  at  end  of  trials. 

charge. 

jectile. 

en- 
dured. 

Type  guns. 

Pounds. 

Pounds. 

8-inch  . . 

Muzzle     insertion,     wrought-iron 
tube  (English). 

35 

180 

817 

Serviceable. 

8-inch  . . 

Muzzle     insertion,     wrought-iron 
tube  (West  Point  Foundry). 

35 

180 

651 

Do. 

8-inch  . . 

Breech     insertion     wronght-iron- 
tube  (West  Point  Foundry). 

35 

180 

783 

Do. 

8-inch  .. 

Muzzle  insertion,  steel  tube  (Mid- 
vale). 

Experimental  guns. 

35 

180 

606 

Do. 

8-inch  . . 

Breeeh  insertion,  steel  tube  (Bo- 
chum). 

35 

180 

456 

Steel  tube  cracked  at  one 
hundred  and  seventy-fifth 
round  and  gun  destroyed 
at  four  hundred  and  fifty- 
sixth  round. 

8-inch  . . 

Chambered;    breech    insertion, 
wrought-iron  tube  (West  Point 
Foundry). 

5.5 

180 

108 

Serviceable. 

9-inch  . . 

Muzzle     insertion,     wrought-iron 
tube  (English). 

(          40 
1          45 

200 
230 

1      502 

Do. 

9-inch  . . 

Breech  insertion,  steel  tube  (Bo- 
chum). 

40 

230 

118 

Do. 

10-inch  . 

Muzzle    insertion,     wrought-iron 
tube  (English), 

75 

400 

33 

Serviceable,  with  repaired 
tube.  The  original  tube 
was  ruptured  longitudi- 
nally early  in  the  proof. 

11-inch  . 

Breech     insertion,     wrought-iron 
tube  (West  Point  Foundry). 

90 

525 

401 

Passed  prescribed  endur- 
ance test  of  400  rounds. 
Defects  developed  in  coil 
welds. 

11-inch  . 

Chambered;    breech    insertion, 
wrought-iron  tube  (West  Point 
Foundry). 

125 

550 

138 

Serviceable. 

12  to  25 

New  construction,   muzzle   inser- 

also 

700 

76 

Do. 

inch. 

tion,   wrought-iron    tube   (West 
Point  Foundry). 

« One  round  with  200-pound  charge  of  powder.  The  greater  number  with  100-pound 
charge. 

The  8-inch  service  rifle  of  this  class  is  14.7  calibers  in  length  of 
bore.  The  charge  is  35  pounds  of  hexagonal  powder,  and  the  pro- 
jectile weighs  180  pounds.  The  results  of  the  latest  trials  with  this 
charge  give  an  average  pressure  in  the  bore  of  30,500  pounds  per 
square  inch,  and  an  initial  velocity  of  1,385  f.  s.  From  trials  made 
at  Sandy  Hook  in  1883,  using  chilled-iron  projectiles,  it  was  shown 
that  the  power  of  the  gun  was  sufiicient  to  more  than  penetrate  8 
inches  of  iron  armor  at  1.000  yards,  thus  making  it  an  effective 
weapon  to  defend  narrow  channels  against  the  passage  of  vessels 
carrying  about  8  inches  of  iron  or  less. 


GUN   MAKING   IN    THE   UNITED    STATES.  27 

CONVERTED   BREECH-LOADING   RIFLES. 

The  recommendation  of  the  board  of  1872  to  test  the  Krupp  sys- 
tem was  carried  out  in  regard  to  the  breech  mechanism  by  its  adapta- 
tion to  the  converted  breech-loading  guns  which  were  tried,  follow- 
ing the  success  obtained  with  the  muzzle-loading  rifles.  In  general 
features  of  the  tube  construction  the  breech-loading  gun  was  made 
like  the  breech-insertion  muzzle-loader.  But  the  jacket  was  made  of 
a  heavy  steel  piece,  which  projected  to  the  rear  to  receive  the  Krupp 
fermeture,  and  this  jacket,  being  larger  than  the  wrought-iron  jacket 
used  in  the  muzzle-loader,  considerably  more  of  the  thickness  of  cast 
iron  about  the  breech  was  removed,  leaving  a  thinner  casing  of  cast 
iron.  To  compensate  for  this,  and  to  add  strength  to  the  breech,  a 
steel  hoop  was  shrunk  upon  the  breech  end  of  the  truncated  casing; 
and,  in  addition  to  the  screw  thread  used  to  secure  the  tube  in  place, 
the  casing  in  this  construction  was  also  shrunk  upon  the  tube  over  the 
length  of  its  jacket.  The  first  8-inch  gun  was  made  and  tried.  The 
steel  used  in  this  gun  was  furnished  by  T^^iitworth,  and  was  of  good 
quality.  The  proof  of  this  gun  was  entirely  successful ;  it  withstood 
636  roimds,  using  the  same  charge  as  the  muzzle-loading  rifle  without 
injury,  and  remained  in  serviceable  condition.  Other  guns  of  8  and 
11  inch  caliber  were  then  ordered.** 

The  orders  given  for  the  manufacture  of  the  converted  8  and  11 
inch  guns  were  suspended  and  canceled  when  the  second  trial  gun 
of  8-inch  caliber  and  the  first  of  11-inch  caliber  failed  under  the 
proof  to  which  they  were  subjected.  These  gims  differed  from  the 
first  experimental  breech-loading  gun  in  being  chambered  to  receive 
increased  charges  of  powder — the  increase  being  for  8-inch,  55  pounds 
instead  of  35,  and  for  11-inch,  130  pounds  instead  of  90.  One  8-inch 
and  the  11-inch  gun  failed  after  a  few  proof  rounds,  by  a  clear  frac- 
ture of  the  steel  breech  piece  in  a  plane  through  the  front  angles  of 
the  slot  for  breechblock.  It  is  important  to  remark  that  in  these 
guns  the  angles  at  the  front  corners  of  the  slot  were  cut  square — a 
feature  which  is  stated  to  have  caused  several  of  the  few  recorded  dis- 

a  An  experimental  12-incb  breech-loading  chambered  howitzer  to  be  con- 
verted from  a  15-inch  smoothbore,  and  four  12-inch  breech-loading  chambered 
rifles  of  new  construction,  but  of  the  same  general  design  as  the  converted 
8-inch  breechloader,  were  also  projected,  and  their  construction  was  begun  in 
1880.  The  12-inch  rifle  was  designed  for  24  calibers  length  of  bore,  wnth  a 
total  weight  of  about  50  tons,  and  use  200  to  .300  pounds  of  powder  with  800- 
pound  projectile.  None  of  these  guns,  however,  were  completed.  It  became 
necessary  to  abandon  the  construction,  because  steel  of  the  requisite  qualities 
could  not  be  supplied.  The  steel  forgings  for  these  guns  were  procured  in  Eng- 
land, and  brought  to  this  coimtry  by  the  contractors,  but  when  submitted  for 
the  inspection  of  the  offlcers  of  the  Ordnance  Department,  the  metal  was  found 
to  be  wholly  unsuitable,  being  materially  below  the  standard  guaranfeed,  and, 
consequently,  the  forgings  were  rejected. 


28  GUN    MAKING    IN    THE    UNITED   STATES. 

astrous  failures  in  guns  made  by  Krupp.  Added  to  this,  the  tests  of 
the  steel  which  ruptured  in  these  guns  showed  a  quality  of  metal 
badly  adapted  to  gim  construction.  Four  specimens  taken  longi- 
tudinally from  the  metal  of  the  8-inch  piece  gave  an  ultimate  tenacity 
varying  from  79,000  to  112,000  pounds  per  square  inch,  and  this 
irregularity  of  strength  was  accompanied  by  an  exceedingly  low 
ultimate  extension,  in  one  specimen  as  low  as  4  per  cent,  and  not 
exceeding  9  per  cent  in  the  best  of  the  four. 

The  11-inch  piece  showed  a  much  poorer  quality  of  steel,  though 
of  an  entirely  different  nature.  The  average  tenacity  was  uniform, 
but  low,  ranging,  for  12  specimens,  about  66,000  pounds  per  square 
inch.  The  elastic  limit  ranged  between  the  low  figures  of  10,000  and 
24,000  pounds  per  square  inch,  and  the  m^tal  was  soft  and  friable  in 
its  nature.  Analysis  showed  that  it  contained  0.247  of  1  per  cent  of 
sulphur.  Subsequently  a  second  8-inch  gun,  made  at  the  same  time 
with  that  just  described,  was  prepared  for  trial  by  rounding  the  front 
corners  of  the  slot.  This  gun  gave  an  excellent  record  in  its  proof 
for  endurance.  It  was  burst  into  many  fragments  at  the  one  hundred 
and  twenty-seventh  round,  but  for  G  rounds  preceding  that  catastro- 
phe had  endured  a  55-pound  charge  of  powder  that  gave  an  average 
of  51,000  pounds  pressure  per  square  inch  in  the  bore,  and  for  15 
rounds  preceding  the  6  named,  an  equal  charge  of  somewhat  slower 
powder,  that  gave  an  average  of  43,600  pounds  pressure. 

It  was  equalh'  unfortunate  for  the  Krupp  breech  mechanism,  and 
for  the  advancement  of  steel  gun  construction  in  this  country,  that 
the  two  gims  should  have  failed  so  soon  in  the  proof.  It  is  not  fair 
to  argue  that  it  was  the  Krupp  mechanism  which  caused  the  failure, 
since  the  steel  was  of  unsuitable  quality,  and  the  after  proof  of  the 
gun,  with  rounded  angles,  indicated  a  good  endurance  of  the  mechan- 
ism, as  did  also  the  proof  of  the  experimental  gun  which  endured  636 
rounds  without  failure;  but  the  failure  of  these  guns  called  particular 
attention  to  that  apparently  ugly  feature  in  the  mechanism — the 
amount  of  metal  cut  away  bv  the  slot — which,  especially  in  large 
guns,  gives  the  appearance  of  longitudinal  weakness.  As  to  manipu- 
lation, and  in  other  respects,  the  Krupp  mechanism,  provided  by  home 
manufacturers,  gave  a  good  degree  of  satisfaction.  The  only  objec- 
tionable feature  of  importance  noted  was  the  tendency  of  the  seat  for 
the  gas  check  to  become  oval,  attributed  to  the  presence  of  the  slot  and 
the  resultant  of  the  longitudinal  pull  which  is  sustained  by  the  sectors 
of  the  metal  left  above  and  below,  and  is  so  unequally  distributed 
throughout  the  cross  section  of  the  jacket.  In  the  converted  3.2-inch 
breech-loading  field  guns  this  mechanism  has  given  no  serious  cause 
for  complaint  in  the  limited  use  to  which  it  has  been  put  in  our 
service.*  In  Germany,  however,  it  has  been  found  necessary,  in  rough 
service,  to  modify  the  Broadwell  ring.     The  large  surface  of  contact 


GUN    MAKING   IN    THE   UNITED    STATES.  29 

between  the  exterior  surface  of  this  ring  and  its  seat  makes  it  diffi- 
cult to  preserve  the  close  adjustment  needed,  and  this  ill  fitting  is 
aggravated  by  the  presence  of  any  dust  or  dirt  in  the  seat.  The 
modification,  which  has  been  applied  with  good  results,  consists 
essentially  in  reversing  the  contour  of  the  ring  and  limiting  the  sur- 
face of  contact  to  a  blunt  rounded  lip  which  co]nes  in  contact  with  the 
seat,  to  seal  the  escape  of  gas.  only  at  the  forward  end  of  the  ring. 
As  regards  the  utility  and  safety  of  the  Krupp  breech  mechanism,  as 
a  whole,  its  long-continued  and  successful  application  in  guns  made 
by  Krupp  place  it  beyond  doubt  as  one  of  the  two  best  systems  now 
in  vogue. 

The  effect  of  the  failure  of  these  guns  in  producing  an  unfavorable 
opinion  upon  the  use  of  steel  in  gun  construction  was  also  marked. 
Not  only  was  this  opinion  generally  diffused,  but  it  was  taken  up 
by  officers  of  our  own  service  and  others  interested  in  the  science  of 
gun  construction.  So  it  was  uphill  work  with  this  metal  for  some 
years  afterwards  to  convince  such  doubters  that  there  was  taking 
place  a  vast  improvement  in  quality  gained  by  knowledge  and  expe- 
rience in  its  manufacture.  Until  finally,  with  more  knowledge  of 
the  quality  of  the  metal  required  for  guns,  all  must  now  turn  to 
steel  to  get  a  metal  that  can  be  readily  made  to  exhibit  the  best  com- 
bination of  the  qualities  required. 

The  two  remaining  guns  recommended  by  the  Board  of  1872 
were  the  9-inch  Sutcliffe  and  the  12-inch  Thompson  breech-loading 
rifles.  Both  of  these  guns  were  made  by  the  Government  and 
tested  at  Sandy  Hook,  but  the  first  was  fired  in  all  only  twenty- 
six  and  the  latter  two  rounds.  Following  this,  in  1876,  the  pieces 
were  sent  to  Philadelphia  for  exhibition  at  the  Centennial,  after 
which  they  were  again  returned  to  Sandy  Hook.  But  thereafter 
no  experiments  were  made  by  reason,  as  it  appears,  that  no  specific 
appropriations  for  the  purpose  were  made  b}^  Congress.  In  each 
of  the  succeeding  years,  1878,  1879,  and  1880,  the  Chief  of  Ordnance 
recommended  without  avail  an  appropriation  of  $117,600  for  the 
tests  of  these  guns,  including  the  Woodbridge  10-inch  rifle,  the 
Lyman  multicharge  gun,  and  the  Mann  8-inch  breech-loading  rifle. 

SUTCLIFFE  y-INCH  BREECH-LOADING  RIFLE. 

In  general  construction  this  gun  consists  of  a  cast-iron  body 
with  a  comparatively  thick  steel  tube  inserted  from  the  rear  and 
terminating  at  the  front  of  the  block,  while  in  rear  of  the  block  and 
its  slot  the  cast-iron  body  is  bored  and  threaded  to  receive  a  movable 
hollow  screw  sleeve,  which  supports  the  block  from  the  rear  and 
through  which  the  charge  is  inserted.  The  breechblock  is  made  in 
the  form  of  a  disk,  and  is  moved  in  its  slot  by  rotating  the 'sleeve. 
A  Broadwell  ring  is  used  as  a  gas  check.     It  was  the  intention  in 


30  GUN   MAKING   IN   THE   UNITED   STATES. 

making  this  gun  to  provide  both  for  a  test  of  the  breech  mechanism 
and  the  principle  of  steel  lining  in  a  cast-iron  body,  and  the  dimen- 
sions given  to  the  parts  were  considered  sufficient  to  enable  the  bore 
to  be  enlarged  to  10  inches  after  firing  250  rounds,  as  a  9-inch  gun. 
The  tube  was  inserted  with  a  slight  play  in  the  casing  and  was 
forced  home  by  hydraulic  pressure.  Shoulders  on  the  exterior  of 
the  tube  prevent  its  forward  movement,  and  it  is  also  held  by  a 
screw  muzzle  collar  and  by  a  couple  of  securing  pins  through  the 
casing.  A  powder  chamber  0.3  inch  larger  in  diameter  than  the  bore 
is  provided,  and  its  axis  is  eccentric  with  that  of  the  bore,  being 
placed  0.05  of  an  inch  above  it.  In  the  26  rounds  fired  the  heaviest 
charge  contained  45  pounds  of  powder  and  a  250-pound  projectile. 
The  maximum  pressure  observed  was  29,250  pounds  per  square  inch. 
The  test  gave  no  measure  of  the  strength  of  the  system  of  tubing, 
owing  to  the  limited  number  of  rounds  fired  and  the  surplus  of 
strength  for  a  9-inch  gun,  but  in  any  event  the  breech  mechanism 
constitutes  its  most  interesting  features.  It  is  difficult  to  explain 
such  features  without  the  aid  of  a  drawing,  but  an  idea  may  be  had 
of  the  slot  in  which  the  block  moves  b}^  supposing  one  side  of  the 
Krupp  slot  left  solid  and  the  opening  made  in  one  side  only.  The 
block  which  moves  in  this  slot  is  a  disk  of  steel — in  this  gun  12.4 
inches  thick,  or,  say,  1^  calibers — which  is  moved  by  means  of  a  steel 
pin  connecting  with  the  movable  screw  sleeve  operated  from  the  out- 
side rear.  The  pin  is  set  in  the  block  near  its  periphery  and  is  free 
to  revolve  in  its  seat  in  the  sleeve.  In  giving  the  sleeve  a  half  revo- 
lution the  pin  is  carried  around  and  the  block  is  constrained  to  move 
in  the  slot,  to  open  or  close  the  breech,  partly  by  rolling  and  partly 
by  sliding.  An  obturator  plate  similar  to  the  Krupp  is  embedded 
in  the  front  of  the  block  to  support  the  Broadwell  ring.  The  block 
is  pierced  with  an  axial  vent.  This  breech  mechanism  has  few  parts 
and  the  motions  are  simple.  It  embodies  the  disadvantage  of  having 
an  unequal  section  of  metal  through  the  breech  just  in  rear  of 
the  place  of  maximum  tangential  strain,  and  where  the  longitudinal 
strain  is  most  felt,  but  to  a  less  degree  perhaps  than  the  Krupp 
mechanism.  It  also  occupies  a  greater  length  of  bore  space  than  the 
French  system.  It  might  be  claimed  to  have  an  advantage  over  this 
last,  for  longitudinal  strength,  because  of  the  continuous  thread  of 
the  breech  screw,  but  the  diameter  of  this  screw  must  be  made  so 
great  as  to  considerably  reduce  the  cross  section  of  metal  that  resists 
the  longitudinal  strain.  But  the  difficulty  found  in  operating  it 
under  fire,  and  that  which  appears  to  be  the  weakest  point,  is  the 
inadequacy  of  the  arrangement  for  controlling  and  moving  the 
block.  The  stud  pin  which  forms  the  only  connection  between  the 
block  and  the  breech  sleeve  is  subject  to  severe  strains,  and  in  a  few 
rounds  fired  it  occurred  that  this  pin  became  bent  and  the  block  was 
operated  with  difficulty. 


GUN    MAKING   IN    THE    UNITED    STATES.  31 

THOMPSON    12-INCH    BREECH-LOADING    RIFLE. 

This  ^n  is  made  of  a  cast-iron  body,  of  the  usual  Rodman  model, 
in  which  is  inserted,  under  a  slight  shrinkage,  a  thin  steel  lining  tube 
that  extends  through  the  bore  and  is  secured  by  a  screw  thread  at 
the  breech  end.  It  was  incomplete  when  received  at  the  proving 
ground  and  in  this  condition  was  fired  two  rounds  before  being  sent 
to  Philadelphia  in  1876,  and  thereafter,  for  reasons  already  stated, 
the  test  was  not  resumed.  In  the  form  of  slot  for  breechblock  it  re- 
sembles the  Sutcliffe  gun.  The  face  of  the  block  when  closed  abuts 
directly  against  the  rear  end  of  the  tube  and  closes  the  opening. 
The  block  is  circular  in  cross  section  and  is  rolled  laterally  in  the 
horizontal  slot  to  open  or  close  the  breech.  It  is  fitted  with  cogs  which 
engage  in  a  toothed  rack  laid  in  the  bottom  of  the  slot.  Power  is 
applied  by  means  of  a  lever  attached  to  a  shaft  or  spindle  which  is 
secured  to  the  center  of  the  block  and  extends  through  the  breech  to 
the  rear,  and  is  there  geared  to  work  in  a  rack.  On  applying  power 
the  spindle  and  block  revolve  together  and  the  spindle  traverses  a 
horizontal  slot  cut  throughout  the  length  of  the  breech  along  one  side 
of  the  loading  channel.  The  charge  is  inserted  through  the  loading 
channel  which  forms  a  prolongation  of  the  bore  to  the  rear.  The  back 
of  the  block  is  faced  with  a  cam,  which,  in  the  act  of  closing  the 
breech,  comes  in  contact  with  a  corresponding  cam  on  the  rear  face  of 
the  slot,  by  means  of  which  the  block  is  forced  forward  until  its 
beveled  face  is  in  close  contact  with  the  end  of  the  tube  fitted  to  re- 
ceive it — thus  closing  the  breech.  Wlien  closed,  the  block  is  supported 
in  rear  about  its  circumference,  except  across  the  opening  made  for 
traversing  the  spindle.  The  width  of  the  cam  bearing  round  the  block 
is  1.5  inches. 

When  the  gun  was  tried  no  means  were  provided  for  locking  the 
block  in  position  when  closed,  nor  was  there  any  provision  for  a  gas 
check  or  vent  proper.  It  was  the  intention  of  the  inventor  to  use 
center-primed  metallic  cartridge  cases,  to  be  discharged  by  a  firing 
pan  passed  through  the  center  of  the  spindle  and  block.  There  are 
no  features  about  this  mechanism,  I  believe,  which  call  for  anj^  special 
commendation  in  the  light  of  present  knowledge.  The  attempt  to  use 
a  metallic  case  for  a  gas  check  was  subsequently  tried  in  the  Yates 
8-inch  breech-loading  riflie,  with  very  poor  success.  The  difficulty  of 
holding  the  block  up  to  place  in  the  Thompson  gun  would  be  a  serious 
one,  and  it  might  be  anticipated  that  the  bearing  surface  of  the  block 
in  rear  would  prove  insufficient,  and  the  longitudinal  strain  to  cause 
disruption  of  the  breech  would  be  besides  wholly  thrown  upon  one 
angle  in  the  slot. 

FIELD  GUNS. 

During  the  period  1873  to  1882  trials  were  also  made  at  Sandy 
Hook  with  breech-loading  field  guns,  and  the  Dean  3.5  mandreled 


32  GUK    MAKING    IX    THE    VNITED   STATES. 

bronze  gun.  The  Dean  giin  was  prociirred  in  1877.  It  was  subjected 
to  a  firing  test  of  50  rounds  which,  so  far  as  it  went,  proved  the  ex- 
cellent quality  of  the  material,  but  it  was  a  muzzle-loading  gun, 
made  after  a  design  already  out  of  date,  and  gave  inferior  ballistic 
results.  The  introduction  of  steel  in  new  constructions  operated 
against  the  extension  of  the  system.  This  system  of  manufacture  has 
been  tried  in  Russia.  Italy,  and  especially  in  Austria.  Avhere,  under 
General  Uchatius'  earnest  supervision,  it  was  finally  introduced  for 
field  and  the  lighter  siege  guns,  but  was  not  successful  in  application 
to  heavier  guns. 

The  three  systems  of  field  guns  principally  tested  were  the  Sutcliffe 
3-inch,  Moffat  3.07-inch,  and  the  converted  3.2-inch  field  gim  with 
Krupp  mechanism,  made  on  the  plans  of  the  Constructor  of  Ord- 
nance. 

The  Sutcliffe  breech-loading  field  gun  was  made  by  converting  a 
3-inch  wrought-iron  rifle,  the  breech  mechanism  being  in  all  essen- 
tial respects  like  that  of  the  9-inch  gun.  The  trial  gun  was  received 
at  the  proving  ground  in  1876:  it  was  fired  53  rounds,  an  average 
charge  being  1:^  pounds  of  powder  and  a  10-pound  projectile,  which 
gave  a  velocity  of  1,109  f.  s.  The  reports  state  that,  so  far  as  tested, 
the  working  of  the  breech  mechanism  was  satisfactory. 

The  Moffat  breech-loading  gun  was  brought  out  in  1873.  The 
body  is  of  steel,  made  from  a  solid  piece.  The  breechblock,  as  in 
the  Mann  gim.  is  secured  by  a  strap  or  breeching  pivoted  on  the 
trunnions;  and  each  arm  of  the  strap  is  supported  by  locking  into 
lugs  on  either  side  of  the  breech  of  the  gun.  The  strap  rests  upon 
the  head  of  the  elevating  screw,  and  the  breech  is  raised  clear  of  it 
for  loading  by  means  of  a  lever  pivoted  on  the  screw.  The  block 
is  hinged  to  the  underside  of  the  breech,  and  has  a  conical  face 
which  fits  closely  in  the  breech.  The  rear  of  the  block  is  wedge 
shaped,  and  in  closing  is  pressed  into  its  seat  by  contact  with  the 
strap.  A^Hien  the  breech  of  the  gun  is  raised  for  loading,  the  block 
revoh'es  backward  and  rests  upon  the  strap.  This  gun  was  fired 
175  rounds,  and  gave  a  velocity  of  1,124  f.  s.  with  a  charge  of  1^ 
pounds  of  powder  and  10^-pound  projectile. 

The  converted  3.2-inch  breech-loading  field  gun.  Krupp  mechan- 
ism, was  first  proposed  in  1878,  and  trials  were  made  with  a  gun  of 
3.17-inch  caliber  in  1879.  Subsequently  the  caliber  was  increased, 
and  the  3.2-inch  was  decided  upon.  The  conversion  consists  in  cut- 
ting off  the  breech  of  a  3-inch  wrought  muzzle-loading  rifle  near 
the  bottom  of  the  bore  and  screwing  in  from  the  rear  a  steel  breech 
receiver  through  which  the  bore  is  prolonged.  The  breechblock 
is  supported  in  the  breech  receiver,  which  also  extends  forward 
some  16  inches  within  the  wrought-iron  body,  inclosing  the  chamber 


GUN    MAKING  IN    THE   UNITED    STATES.  33 

and  forming  the  rear  portion  of  the  bore.  The  breechblock  is  of 
the  Krupp  pattern  made  in  this  country,  and  the  Broa dwell  ring  is 
used  for  a  gas  check.  B}-  chambering,  the  power  of  this  gun  was 
much  increased  over  that  previously  obtained  with  guns  of  like 
caliber,  and  as  its  trials  were  satisfactory,  the  gun  was  provision- 
ally adopted  for  trial  in  service.  A  few  have  been  made  and  issued 
for  service  and  are  still  in  use.  In  trials  reported  in  1883  the  first 
gun  shows  a  record  of  849  rounds  as  far  as  tested.  In  prolonged 
firing  the  principal  difficult}^  was  found  with  the  gas  check,  Avhich 
became  scored  and  allowed  the  escape  of  gas.  With  a  new  gas  check 
275  rounds  were  fired  without  material  injury,  and  it  was  concluded 
that  one  check  would  be  good  for  about  300  rounds.  The  powder 
charge  is  3  pounds,  and  the  solid  shot  weighs  12  pounds.  With  this 
charge  the  pressure  averages  25,633  pounds,  and  the  muzzle  velocity 
is  1,548  f.  s.  The  range  at  20°  elevation  is  5,879  yards,  or  3.34  miles; 
at  15°,  4,978  yards;  at  10°,  3,986  yards,  and  "at  5°,  2,508  yards. 
The  gini  weighs  826  pounds,  and  the  muzzle  energy  of  shot  per 
pound  of  piece  is  541.2  foot-tons. 

To  sum  up  the  results  of  the  ten  years  ending  in  1882,  which  were 
devoted  to  the  development  of  guns  recommended  by  the  boar(J  of 
1872  (appointed  by  act  of  Congress)  :  The  Woodbridge  brazed, 
wire-wound  gun,  and  the  Hitchcock  gun,  were  thoroughly  tried  with 
results  already  mentioned — the  former  presenting  great  difficulties 
in  manufacture  and  failing  under  proof,  and  the  latter  failing  in 
manufacture.  The  Sutcliff'e  9-inch,  Thompson,  and  Mann  guns  were 
tested  to  a  very  limited  extent,  with  results  in  the  case  of  the  first 
two  which  did  not  at  best  give  any  marked  prospect  of  success ;  but 
Congress,  by  its  refusal  to  appropriate  money  for  the  purpose,  nega- 
tived an  exhaustive  trial  of  them.  Lyman's  multicharge  gim  comes 
under  the  same  category;  however,  tests  already  made  at  Reading 
with  the  same  gun  that  was  awaiting  trial  at  this  time  indicate  that 
the  interests  of  the  country  did  not  suffer  in  the  failure  to  test  it 
further. 

The  successful  issue  of  the  period  was  the  Ordnance  system  of 
converted  muzzle-loading  rifles  whereby  there  was  placed  in  service 
210  8-inch  rifles,  each  having  at  1,000  yards  range  more  than  double 
the  power  and  three  times  the  accuracy  of  the  10-inch  smooth- 
bore which  it  replaced,  besides  made  strong  enough  by  the  conver- 
sion to  endure  fully  as  many,  if  not  more,  rounds  as  a  rifled  gun 
than  the  old  smoothbore  would  stand  with  its  light  charges.  And 
however  poorly  these  rifles  may  now  appear  in  comparison  with  the 
modern  gun,  this  much  must  be  remembered — if  a  war  should  arise 
to-morrow  they  are  the  only  reliable  rifles  that  we  have  available  for 
seacoast  defense.     The  power  of  this  gun  to  penetrate  8  inches  of 

7733—08 3 


34  GUN    MAKING    IN    THE    UNITED   STATES. 

iron  armor  with  backing,  or  6  inches  of  steel  armor,  at  1,000  yards 
range  makes  it  eifective  against  a  large  proportion  of  the  war  ships 
of  the  world.  It  would  of  course  be  of  little  use  in  firing  against 
the  heavil}^  armored  ships,  but  these  constitute  perhaps  one-fourth 
only  of  the  whole  number  of  such  ships. 

The  11 -inch  rifle  of  the  same  construction  was  successfully  tested, 
but  was  not  made  a  service  type,  which  was  a  wise  course,  seeing  the 
relative  disparity  of  this  caliber  to  those  of  other  countries,  when 
it  became  a  question  whether  to  make  these  guns  in  quantity,  and 
noting  also  the  present  efficiency  of  the  15-inch  smoothbore  with 
its  increased  charge.  In  other  words,  it  did  not  then  appear  to  be 
a  paying'  investment — and,  with  our  present  knowledge,  it  would 
appear  much  less  so— to  sacrifice  a  15-inch  smoothbore  to  make  an 
11-inch  muzzle-loading  rifle.  The  converted  8-inch  breech-loading 
rifle  of  the  same  general  construction,  with  Krupp  mechanism, 
unchambered,  and  firing  a  charge  of  35  pounds  of  powder  was  a 
practical  success.  The  principal  utility  of  the  proof  of  this  gun  lay 
in  the  trial  of  the  breech  mechanism;  the  gun  proved  abundantly 
strong  to  withstand  the  charge  which  was  used,  but  the  design  could 
not  be  adopted  as  a  service  pattern,  because  it  presented  the  disad- 
vantage of  increased  cost  with  no  corresponding  increase  of  power 
or  efficiency  over  the  muzzle-loader.  The  next  step  in  the  develop- 
ment of  this  system  was  to  obtain  a  satisfactory  increase  of  power  for 
the  converted  breechloaders  (8  and  11  inch)  by  chambering  to  use 
a  largely  increased  charge  of  powder,  and  to  extend  the  system  to  nev/ 
constructions  of  large  caliber,  with  increased  length  of  bore  to  give 
high  power.  The  first  8  and  11  inch  guns  failed,  we  may  infer, 
because  of  the  square  angles  of  the  slot,  although  the  steel  used  in 
them  was  not  of  suitable  quality.  The  second  8-inch  gun,  with 
rounded  angles  in  the  slot  and  the  same  make  of  steel,  burst  at  the 
one  hundred  and  twenty-seventh  round  after  enduring  a  series  of  high 
pressures  ending  with  six  consecutive  fires,  giving  pressure  running 
uniformly  about  50,000  pounds  and  over.  The  inevitable  conclusion 
from  these  trials  was  that  this  system  of  converted  breechloaders 
did  not  possess  the  margin  of  strength  which  would  warrant  its 
introduction  in  service.  The  extension  of  the  system  to  large  calibers 
of  new  construction  was  abandoned,  because  it  was  impracticable  to 
obtain  a  suitable  quality  of  steel  in  the  forms  required  by  the  design. 
One  lesson  may  at  least  be  learned  from  what  took  place  in  these 
ten  years,  and  that  is  that  success  in  gim  making  depends  not  upon 
the  test  and  trials  of  different  plans,  however  numerous,  but  upon  a 
steady  and  persistent  effort  upon  one  system;  and  when,  as  in  our 
own  country,  the  sums  appropriated  for  such  purposes  are  small  in 
amount  this  course  offers  the  only  means  of  reaching  any  degree  of 
success  whatever. 


TIL 

The  Conclusions  of  Boards  and  Committees  Appointed  by  Con- 
gress— Money  Expended  for  the  Purchase  of  Cannon  During 
Twenty  Years — Recent  Plans  of  Gun  Construction — The 
Multicharge  Gun — The  Mann  and  the  Yates  Breech-Mech- 
anism— The  Slotted  Screw  Breech  Mechanism. 

Coming  iioAv  to  a  later  period,  the  course  of  legislation  in  Congress, 
which  governs  these  matters,  has  been  such  as  to  leave  all  questions  of 
policy  in  a  state  of  the  greatest  uncertainty,  and  we  find  the  War 
Department  laboring  under  the  most  adverse  circumstances  in  endeav- 
oring to  further  the  manufacture  of  the  best  type  of  guns  recom- 
mended by  the  Logan  committee,  or  the  Senate  ordnance  report  of 
1883. 

Beginning  with  the  appointment  of  the  Getty  Board  in  188L  every 
year  thereafter,  except  1882.  when  the  report  of  that  board  was  under 
consideration  in  Congress,  has  been  marked  by  the  appointment  of 
a  new  board  pursuant  to  act  of  Congress,  until  finally  the  subject  of 
boards  reached  a  period  of  at  least  temporary  exhaustion,  when  the 
report  of  the  Fortification  Board  was  brought  out  in  1886.  In  that 
year,  and  in  the  present,  there  was  no  board  designated,  but  neither 
was  there  any  fortification  bill  passed. 

The  Board  on  Heavy  Ordnance  and  Projectiles,  of  which  General 
Getty,  an  artillery  officer,  was  president,  was  appointed  pursuant  to 
the  act  of  Congress  appoved  March  3,  1881,  and  submitted  its  report 
in  May,  1882.  The  Gun  Foundry  Board  was  appointed  pursuant  to 
the  act  of  March  3.  1883;  the  Armament  Board  pursuant  to  the  act 
of  July  5,  1884;  and  the  Fortification  Board  pursuant  to  the  act  of 
March  3,  1885.  Besides  which,  in  the  same  years,  we  have  had 
carefuj  and  detailed  examinations  and  reports  on  the  question  of 
heavy  ordnance  from  the  Senate  committer,  of  which  Senator 
Logan  was  chairman,  appointed  August  2,  1882:  the  Senate 
Select  Committee  on  Ordnance  and  War  Ships,  with  Senator  Hawley 
as  chairman,  appointed  July  3,  1884;  and  a  similar  House  com- 
mittee, with  Mr.  Randall  as  chairman,  appointed  July  6,  1884.  There 
is  also  the  standing  committee  of  the  Senate,  with  Senator  Dolph 
as  chairman,  which  has  charge  of  matters  pertaining  to  ordnance. 
The  Select  Committees  on  Ordnance  and  War  Ships  of  the  Senate 
and  House  completed  and  submitted  their  reports  in  1886.  It  is 
not  my  purpose  here  to  analyze  the  able  reports  of  all  these  com- 
mittees and  boards;  they  contain  a  vast  amount  of  valuable  infor- 

35 


36  GUN   MAKING   IN   THE    UNITED   STATES. 

mation  upon  the  subject  which  we  can  only  regret  has  been  put  to  so 
little  practical  use,  in  so  far  as  the  land  defenses  are  concerned.  Of 
all  the  subjects  treated  in  these  reports  (if  we  omit  the  Armament 
Board,  which  was  convened  for  a  distinct  purpose  apart  from  this 
question)  there  was  one  of  all  others  upon  which  there  is  a  unanimity 
of  opinion,  either  explicitly  expressed  or  directly  implied,  in  their 
conclusions,  namely:  That  the  solvtion  of  the  gun  question  lies  in 
the  manufacture  of  the  huilt-up  forged-steel  gun,  and  that  the  indus- 
try of  snaking  forged  steel  for  such  guns  should  he  established  in 
this  country. 

Another  matter  which  also  received  general  commendation  was 
that  the  recommendation  of  the  Gun  Foundry  Board  in  regard  to 
the  establishment  of  Government  factories  (for  the  Army  and  Navy), 
with  capacity  to  manufacture  a  limited  number  of  these  guns  per 
annum,  should  be  adopted. 

But  the  conclusions  of  these  committees  and  boards  have  been 
very  useful  in  helping  the  Navy  to  get  appropriations  for  this  class 
of  guns  in  the  quantities  needed  for  vessels  in  course  of  construction. 
And  now  that  the  policy  of  making  them  has  been  definitely  inaugu- 
rated in  one  branch  of  the  Government  service,  it  will  surely  be  ex- 
tended to  the  land  service.  It  has  been  said  that  the  Ordnance  Depart- 
ment has  expended  millions  and  millions  on  guns  and  has  nothing  to 
show  for  it.  It  may  be  useful  information  then  to  state  the  fact 
that  the  total  amount  expended  for  cannon  in  the  twenty  years 
beginning  July  1,  1866,  and  ending  June  30,  1886,  by  the  Ordnance 
Department,  did  not  exceed  one  and  one-half  millions  of  dollars. 
This  does  not  include  the  amounts  expended  from  the  appropriations 
for  testing  experimental  guns  and  various  inventions,  including  dyna- 
mite, powder,  projectiles,  and  material  for  service  and  reserve;  but 
it  does  include  the  first  cost  of  all  the  cannon  procured  in  the  twenty 
years,  and  in  addition  what  had  been  expended  upon  those  in 
course  of  construction  at  the  end  of  the  period.  It  covers  the  cost 
of  the  plant  erected  for  the  Woodbridge  gun,  the  Hitchcock  gun,  the 
money  otherwise  expended  for  those  guns,  and  all  other  experimental 
guns,  and  also  of  the  following  service  cannon — 318  in  number — 
which  are  now  in  use  or  available  for  issue,  viz : 

1  20-inch  aud  26  15-inch  Rodman  smoothbores. 
1  12:i-inch  tubed  muzzle-loading  rifle. 
.5  11-inch  I 

1  10-inch  I  jimxzle-loading  converted  rifles. 
210  8-inch   | 

4  8-inch  breecli-loading  converted  rifles. 

1  12-inch  muzzle-loading  rifled  howitzer. 

1  8-inch  breech-loading  steel  rifle. 

7  3.2-inch  converted  breech-loading  rifles. 
25  3.2-inch  steel  breech-loading  rifles. 
36  steel  Hotchkiss  breech-loading  mountain  guns. 


GUN   MAKING   IN    THE   UNITED    STATES.  37 

This  sum  of  money,  covering  twenty  j^ears'  expenditure  for  gun 
making  for  the  War  Department,  is  just  equal  to  the  amount  allowed 
for  the  completion,  exclusive  of  armament,  of  one  of  the  new  steel 
cruisers,  for  which  we  are  expected  to  afford  harbors  of  refuge. 

RECENT    PLANS    OF    GUN    CONSTRUCTION. 

We  now  turn  to  the  guns  of  the  present  period,  which,  for  authority 
to  make  by  the  War  Department,  are  the  outcome  of  the  deliberations 
of  the  Senate  Ordnance  Committee  of  1883,  from  testimony  taken  by 
that  committee,  from  plans  submitted  to  it,  and  from  a  review  of  the 
recommendations  of  the  Getty  Board  of  1881.  The  recommendations 
of  this  committee  were  embodied  in  the  fortification  bill  of  1883. 
That  act  authorized  the  continuance  of  the  conversion  of  10-inch 
smoothbores  into  8-inch  muzzle-loading  rifles,  and,  in  addition,  the 
trial  of  5  different  systems  of  gun  construction  and  two  distinct 
types  of  breech  mechanism,  as  follows: 

1.  Built-up  forged-steel  breech-loading  rifles  with  slotted  screw  breech  closure. 

2.  Cast-iron  (simple)  breech-loading  rifles  with  slotted  screw  breech  closure. 

3.  Combined  cast-iron  and  steel  built-up  breech-loading  rifles,  and  rifled  mor- 
tars on  the  same  system,  with  slotted  screw  breech  closure. 

4.  Wire-wound  breech-loading  rifles. 

5.  The  multicharge  gun. 

6.  The  Mann  breech  mechanism. 

7.  The  Yates  breech  mechanism. 

The  two  types  of  Tbreech  mechanism  were  selected  by  the  Chief  of 
Ordnance,  under  the  requirements  of  the  act  which  directed  him  to 
"  select  from  the  many  breech-loading  devices  offered  to  the  Getty 
Board  and  Committee  on  Ordnance  two  that  promise  the  greatest 
success  "  for  test  at  the  cost  of  the  Government. 

The  five  systems  of  construction  as  such,  based  on  various  plans, 
had  all,  except  the  cast-iron  rifle  pure  and  simple,  received  the  recom- 
mendation of  the  Getty  Board.  The  simple  cast-iron  rifle  was  not 
recommended  by  the  Getty  Board,  but  was  inserted  in  the  act  of  1883, 
as  stated: 

In  lieu  of  such  of  the  guns  the  construction  of  which  has  not  yet  been  com- 
menced, as  were  provided  for  by  the  act  making  appropriations  for  fortifications, 
etc.,  for  the  fiscal  year  ending  June  30,  1881. 

The  Government  had  procured  the  iron,  and  preparations  had  been 
made  at  the  South  Boston  Foundry  for  the  castings  here  alluded  to, 
which  were  intended  for  the  12-inch  breechloaders  that  could  not 
be  made  for  lack  of  a  proper  quality  of  steel  for  breech  receivers. 

Three  of  the  systems,  the  built-up  steel,  the  simple  cast  iron,  and 
the  multicharge,  and  the  two  types  of  breech  mechanism  contem- 
plated in  the  act  of  1883,  have  been  subjected  to  trial;  another,  the 
combined  cast  iron  and  steel,  has  been  submitted   to  partial  trial 

/ 


38  GUN    MAKING    IN    THE    UNITED   STATES. 

onh'  ill  the  proof  of  a  12-inch  muzzle-loading  rifled  mortar  hooped 
with  steel,  while  the  rifles  made  on  the  same  system  are  in  a  more  or 
less  forward  state  of  completion,  which  has  been  arrested  for  two 
years  past  through  the  lack  oi  funds  to  pay  for  them,  and  the  remain- 
ing one.  the  wire-wound,  is  in  the  same  category  as  the  guns  just 
named ;  work  on  two  of  these  wire  guns,  which  has  been  in  progress 
at  Watertown  Arsenal,  is  stopped  for  lack  of  money. 

Of  the  plans  of  guns  under  consideration,  all  those  exemplifying 
the  built-up  steel,  the  simple  cast  iron,  and  the  combined  cast  iron 
and  steel  guns,  were  made  by  the  Ordnance  Office.  The  plans  of  the 
wire-wound  guns  are  due  to  Doctor  Woodbridge.  Mr.  Haskell  is 
the  exponent  of  the  multicharge  gun.  The  Mann  and  Yates  breech 
mechanisms  are  designated  by  the  names  of  their  designers,  and  these 
gentlemen  each  supervised  the  construction  of  the  gun  embochdng  his 
plan.  All  work  done,  and  material  furnished  for  the  manufacture 
and  test  of  the  guns  has  been  at  the  expense  of  the  Government,  ex- 
cept for  the  multicharge  gun,  which  was  furnished  at  private  expense, 
and  the  costs  of  the  tests  only  paid  by  the  Government. 

THE  MULTICHARGE  GUN. 

The  principal  feature  of  this  gun  is  well  known  to  consist  in  the 
application  of  the  accelerating  principle  as  applied  to  the  action  of 
the  powder  upon  the  projectile,  and  this  is  sought  to  be  obtained  by 
using  a  series  of  powder  charges  placed  in  jjockets  at  intervals  along 
the  bore  near  the  breech,  which  are  intended  to  be  ignited  by  the  in- 
flamed gases  of  the  breech  charge  following  the  passage  of  the  pro- 
jectile over  the  opening  of  each  powder  pocket  into  the  bore.  The " 
breech  charge  is  relatively  light  to  give  a  gradual  impetus  to  the  pro- 
jectile, which  is  placed  immediately  in  front  of  it  and  in  rear  of  all 
the  pockets.  The  mechanical  difficulties  in  this  construction  are  many, 
but  two  of  the  most  important  are :  First,  the  necessitj'^  for  a  perfect 
closure  of  the  gas  escape  at  the  base  of  the  projectile,  to  prevent  a 
premature  ignition  of  any  of  the  charges  in  the  pockets;  second, 
the  difficulty  of  making  a  gun  of  this  kind  strong  enough  to  withstand 
even  the  reduced  pressures  which  may  be  obtained  by  an  application 
of  the  principle.  This  last  is  especially  important,  for  when  we  talk 
about  safe  pressures  in  a  gun  it  is  of  course  only  a  relative  term  and 
applicable  to  tlie  particular  gun  under  consideration.  As  for  instance, 
a  pressure  of  50,000  pounds  has  been  found  quite  as  safe  for  a  tubed 
converted  gun  with  a  cast-iron  body  as  27,000  pounds  for  the  tubed 
multicharge  giiii  with  a  cast-iron  body,  since  both  of  the  guns  rup- 
tured under  these  pressures;  only  that  the  converted  gun  stood  a 
total  of  127  rounds,  and  the  multicharge  a  total  of  33  rounds,  before 
its  first  failure,  and  of  53  rounds  up  to  final  rupture. 


GUN   MAKING   IN    THE   UNITED    STATES.  39 

The  brief  account  that  I  can  give  of  this  invention  is  taken  from 
statements  made  by  its  proprietors  before  the  Board  of  1872  and  the 
Getty  Board,  and  the  reports  of  some  officers  who  have  witnessed  its 
test.  The  system  was  patented  by  A.  S.  Lyman,  who  commenced  to 
make  experiments  to  test  the  merits  of  his  invention  to  have  it  brought 
into  use  about  1856.  Of  the  various  experiments  that  may  have  been 
made  we  have  accounts  of  the  performance  of  three  guns  only,  viz,  a 
2|-inch  gim  tested  at  the  AVashington  Navy- Yard,  a  6-inch  gim  tested 
at  Reading,  Pa.,  in  1870,  and  the  6-inch  gini  which  was  tested  at 
Sandy  Hook,  in  1883-84.  The  most  striking  experiments  otherwise 
described  were  made  with  a  so-called  gun,  but  rather  a  small-arm 
tube,  10  feet  10  inches  long,  one-half  inch  caliber,  giving  the  enormous 
proportions  of  260  calibers  length  of  bore.  In  this  tube  was  arranged 
one  breech  charge  and  five  additional  pocket  charges.  The  bullet  was 
of  steel,  18  calibers  in  length.  It  is  stated  that  with  a  total  powder 
charge  of  8^  ounces,  and  7^  ounces,  in  the  steel  bullet,  a  penetration 
was  obtained  through  12  plates  of  boiler  iron  bolted  together;  each 
plate  was  something  over  three-eighths,  of  an  inch,  and  the  total 
thickness  was  5^  inches.  This  result  showed  a  penetration  of  10^ 
calibers.  The  initial  velocity  of  the  bullet  was  not  measured,  but  a 
computation  by  the  engineer  of  the  company  made  it  3,000  f.  s. 
Carrying  the  same  proportions,  and  assuming  corresj^onding  results 
with  a  9-inch  gun,  there  would  truly  appear,  as  an  advocate  of  the 
system  has  claimed,  a  penetration  of  7  feet  lOi  inches  of  iron  armor, 
and  he  might  have  added  the  gun  would  be  195  feet  long  and  the  pro- 
jectile 13^  feet  long.  However,  a  better  judgment  can  be  formed  by 
showing  the  actual  results  obtained  with  the  guns  constructed,  as  this 
is  the  only  safe  guide  in  such  matters. 

The  2|-inch  gun  at  the  Washington  Navy- Yard  penetrated  a  target 
of  wrought-iron  plates  5  inches  thick,  backed  by  18  inches  of  solid 
oak  timber.  This  gave  a  penetration  of  "  more  than  2  calibers."  The 
firing  was  done  at  point-blank  range,  200  yards,  with  a  total  charge 
of  6f  pounds  of  powder  and  a  hardened  steel  projectile  weighing  19f 
pounds.  This  gun  was  afterwards  fired  at  Sandy  Hook  for  velocity ; 
the  maximum  obtained  was  1,929  f.  s.  with  10  pounds  of  powder  and 
8-pound  projectile. 

An  account  is  given  of  13  rounds  fired  from  the  6-inch  gun  at 
Reading,  Pa.,  in  1870.  This  gun  had  four  accelerating  pockets  and 
a  total  weight  of  about  11,000  pounds.  The  initial  velocity  was  meas- 
ured for  6  rounds,  of  which  the  best  record  is  1,093  f.  s.  To  quote 
from  Captain  Prince's  report  of  the  trial  which  he  witnessed: 

The  large  local  pressures  and  moderate  velocities  developed  in  this  trial,  where 
precisely  an  opposite  state  of  things  might  reasonably  have  been  looked  for,  can 
only  be  explained  by  supposing  that  the  pocket  charges  in  some  cases  became 
ignited  before  the  projectile  has  passed  over  their  embouchures. 


40  GUN    MAKING    IN    THE    UNITED   STATES. 

This  is  the  gun,  I  believe,  which  was  taken  to  Sandy  Hook  for  trial, 
pursuant  to  the  recommendation  of  this  sj'stem  by  the  Board  of  1872. 

The  trials  at  Sandy  Hook  in  1883-84  were  made  with  a  new  6-inch 
gun  completed  at  Heading,  Pa.,  in  1883.  This  gun,  weighing  25  tons, 
was  made  of  a  cast-iron  body,  lined  throughout  its  length  with  a  steel 
tube,  chambered  for  the  breech  charge,  and  having  a  length  of  bore 
equal  to  46  calibers.  A  breech-closing  mechanism  enabled  the  inser- 
tion of  the  projectile  and  breech  charge  from  the  rear,  and  the  four 
powder  pockets  were  loaded  by  pouring  the  powder  into  a  channel 
connecting  w^ith  each  pocket  from  the  exterior.  The  typical  method 
of  loading  consisted  in  using  five  different  kinds  of  powder  in  the 
separate  charges — relatively  slow  burning  in  the  breech  charge  and  in- 
creasing in  fineness  of  granulation  and  quickness  of  burning  for  each 
successive  pocket  forward.  In  the  later  rounds  of  the  proof  this 
arrangement  was  modified  to  use  two  powders  of  the  same  granula- 
tion, but  of  different  brand  in  the  two  pockets  next  the  breech  charge. 

The  jDroof  was  begun  with  a  charge  of  12  pounds  of  powder  in  the 
breech  and  the  pockets  emp^t3^  This  round  gave  a  velocity  of  1,067 
f.  s.,  w^ith  a  projectile  weighing  108  pounds.  Working  gradually  up 
by  increasing  the  number  of  jDockets  loaded  and  the  total  powder 
charge  at  the  same  time,  at  the  thirteenth  round  the  full  number  of 
five  charges  was  first  used.  In  this  round  the  total  weight  of  powder 
was  83  pounds  and  projectile  109  pounds.  The  pressure  within  the 
chamber  and  pockets  reached  about  20,000  pounds,  and  the  initial 
velocity  was  1,735  f.  s.  The  firing  was  then  continued  with  varjdng 
charges  of  powder  and  projectiles  up  to  the  thirty-third  round,  when 
the  tube  was  cracked  over  a  length  of  9  feet  from  the  muzzle  to  a 
point  near  the  foremost  pocket.  The  pressure  in  these  rounds  varied 
in  the  different  charge  receptacles  from  a  minimum  of  18,000  to  29,000 
pounds,  which  was  the  maximum  record  of  pressure  obtained  from 
the  gauges  placed  in  the  breech  and  in  eaoh  of  the  four  pockets.  The 
highest  record  of  velocity  in  this  trial,  which  appears  also  to  be  the 
highest  yet  obtained  from  a  6-inch  multioharge  gun,  was  2,101  f.  s., 
obtained  with  a  total  powder  charge  of  90  ^xiirnds  and  a  projectile 
weighing  71  pounds.  The  gun  was  then  strengthened  by  shrinking 
several  steel  bands  over  the  chase — the  only  part  where  the  form  of 
the  gun  admitted  the  employment  of  this  strengthening  pi'ocess.  The 
proof  was  then  continued  up  to  the  fifty-third  round,  when  the  cast- 
iron  body  was  cracked  and  the  piece  permanently  disabled.  The 
highest  pressure  that  the  gun  had  to  endure  in  the  proof  was  an 
exceptional  record  of  31,550  pounds — an  average  of  the  pressures  with 
full  charges  being  about  27,000  pounds  per  square  inch.  The  best 
record  of  energy  obtained  during  the  proof  was  given  with  a  total 
powder  charge  of  116  pounds  and  projectile  four  calibers  in  length 
weighing  152  pounds,  for  which  the  velocity  was  1,801  f.  s.  and  muz- 
zle energ}'  3,422  foot-tons. 


GUN    MAKING   IN    THE    UNITED    STATES.  41 

I  have  no  desire  to  pose  in  public  as  a  hostile  critic  of  the  multi- 
charge  system  exemplified  in  the  guns  just  mentioned,  but  rather  the 
reverse,  seeing  the  methods  of  attack  that  are  used  against  those  who 
honestly  oppose  it.  A  large  amount  of  private  capital  has  been  ex- 
pended in  the  attempts  to  perfect  the  gun,  and  experiments  with  it 
were  earnestly  pursued  for  many  years.  If  the  principle  were  really 
valuable,  we  should  have  expected  in  the  latest  model  some  conclu- 
sive evidence  to  that  effect.  The  present  status  of  these  guns  is  a 
matter  of  public  concern,  and  the  conclusion  which  I  draw  from  the 
actual  results  obtained  is  that  the  principle  is  not  valuable  in  the 
present  advanced  state  of  the  art  of  gun  construction.  A  higher 
energy  and  a  greater  penetration  than  the  multicharge  gun  has  shown 
is  a  matter  of  every-day  record  with  guns  using  a  single  charge  of 
powder,  and  the  greater  effect  of  the  single-charge  gun  is  produced 
at  a  much  less  cost  for  original  construction  and  for  maintenance,  and 
also  with  a  much  safer  pressure  in  the  gun.  A  pressure  of  50,000 
pounds,  of  which  only  about  70  per  cent  is  needed  for  the  service  of 
the  piece,  is  entirely  safe  for  a  single-charge  steel  gun,  but  what  a 
multicharge  steel  gun  woidd  stand  is  highly  problematical.  A  com- 
parison of  cast-iron  lined  construction  has  shown  a  better  endurance 
for  the  single-charge  giui  under  50,000  pounds  pressure  than  for  the 
multicharge  under  27,000  pounds.  Probably  the  relative  merits  of 
steel  construction  would  be  about  the  same.  Most  emphatically,  then, 
a  higher  energy  has  not  been  obtained  with  this  gun,  with  its  succes- 
sive charges  and  with  moderate  and  safer  pressures,  than  can  result 
from  any  gun  of  the  same  caliber  using  only  one  charge,  nor  is  there 
any  ground  to  hope  that  such  a  result  can  be  expected. 

THE    MANN    BREECH    MECHANISM. 

The  j)rinciple  involved  in  the  Mann  breech  mechanism  is  to  accom- 
plish a  complete  separation  of  the  longitudinal  from  the  tangential 
strains  due  to  firing  a  gun.  As  illustrated  in  the  6. 5-inch  rifle,  tested 
in  1884,  it  comprises  a  heavy  breechblock  supported  and  threaded  in 
a  transom,  having  no  connection  with  the  body  of  the  gun  at  the 
breech.  The  ends  of  the  transom,  which  project  beyond  either  side 
of  the  breech,  are  fastened  in  heavy  side  straps  that  extend  forward 
and  loop  over  the  trunnions  of  the  gun  body.  The  gun  body  proper 
is  made  with  a  tube  open  from  end  to  end.  and  is  counterpoised  at  the 
trunnion  bearings  in  the  straps.  The  trunnions  proper,  which  con- 
nect the  whole  system  with  the  carriage,  form  a  part  of  the  side  straps, 
and  these  straps  support  the  longitudinal  strain  due  to  the  pressure 
on  the  breechblock.  The  breech  is  opened  or  closed  by  raising  or 
lowering  the  breech  of  the  gun  body,  which  revolves  about  its  own 
trunnions.  The  breechblock  when  closed  covers  the  breech  end  of 
the  tube  and  supports  the  gas-check  ring. 


42  GUN   MAKING   IN   THE   UNITED   STATES. 

The  Mann  breech  mechanism  has  been  known  and  tried  at  different 
times  for  a  number  of  years.  Mr.  Mann  stated  to  the  Logan  Com- 
mittee that  in  1862  a  3-inch  gun  was  fired  at  Battery  Fox,  Wash- 
ington, D.  C,  437  times  under  the  direction  of  Admiral  Dahlgren, 
and  that  during  this  firing  the  gun  was  fired  96  times  in  seventy-six 
minutes  without  interruption.  In  the  same  year  the  Navy  Depart- 
ment gave  him  an  order  for  an  8-inch  breech-loading  rifle  made  on 
the  same  plan.  This  gun  was  completed  in  September,  1873.  A 
number  of  trials  were  made  with  this  gun  by  the  Navy  Department, 
and  it  was  then  turned  over  to  the  War  Department.  Tests  were 
made  with  it  by  Captain  Edson,  of  the  Army  Ordnance  Department, 
at  Fort  Monroe  Arsenal,  Virginia,  in  1865.  He  found  the  working 
of  the  breech  mechanism  to  be  fairly  satisfactory.  This  was  the 
gun  considered  by  the  board  of  1872,  and  pursuant  to  the  recom- 
mendations of  that  board,  and  the  plans  of  the  inventor,  the  piece 
was  altered  in  several  particulars  and  transformed  into  a  gun  of  8.4 
inches  caliber.  Previous  to  this  transformation  the  gun  had  been 
fired  fifty  times.  The  only  tests  made  of  the  piece  after  this  were 
two  rounds  fired  at  the  foundry,  and  eleven  at  Sandy  Hook,  in  1875. 
This  record  was  sufficient  to  induce  the  Chief  of  Ordnance  to  select 
this  mechanism,  under  the  act  of  1883.  as  one  of  the  two,  out  of  all 
those  submitted  to  the  Getty  Board,  which  should  be  subjected  to 
trial  and  test.  A  new  gun,  conforming  to  patents  taken  out  by  the 
inventor  in  1882  and  made  under  his  supervision,  was  then  procured 
at  the  cost  of  the  Government.  This  gun.  as  already  stated,  was 
tested  at  Sandy  Hook  in  1884.  The  test  was  made  under  the  Board 
for  Testing  Rifled  Cannon,  instituted  as  a  permanent  board  by  the 
act  of  July  5,  1884,  which  provides  that  hereafter  all  rifled  cannon 
manufactured  at  the  cost  of  the  United  States  shall  be  publicly 
subjected  to  the  proper  test  for  the  determination  of  the  endurance 
of  the  same  *  *  *  and  further,  if  such  guns  shall  not  prove 
satisfactorv  thev  shall  not  be  put  to  use  in  the  Government  service. 
The  history  of  this  test  is,  in  brief,  given  in  the  report  of  the  board  : 

This  guu,  having  burst  at  the  twenty-fourth  round,  its  endurance  was  not 
satisfactory  to  the  board,  and  hence  it  can  not  recommend  that  it  be  put  to  use 
in  the  Government  service.  The  highest  recorded  pressure  was  27,500  pounds 
per  square  inch.  The  failure  of  the  gun  was  occasioned  by  the  fracture  of  the 
transom  near  its  left  tenon.  This  transom  was  made  of  a  superior  quality 
of  Whitworth  steel,  and  the  fracture  showed  no  defects  in  the  metal.  There 
was  evidence  during  the  firing  that  the  side  straps  did  not  hold  the  breechblock 
up  to  its  place,  as  the  breech  of  the  guu  body  was  slightly  raised  from  its  place 
by  the  shock  of  discharge. 

The  principle  of  this  breech  mechanism  appears  to  be  a  mistaken  one :  the 
longitudinal  strain  in  a  well-built  gun  does  not  materially  detract  from  the 
tangential  strength.  Some  constructions,  as  in  the  case  of  wire  guns,  may 
require  a  special  provision  to  obtain  the  necessary  longitudinal  strength,  but 
these  should  form  an  integral  part  of  the  gun,  and  be  solidly  and  firmly  built 


GUN   MAKING   IN   THE   UNITED   STATES.  43 

into  the  structure.  It  would  appear  that  auy  attempt  made  to  separate  the 
parts  designed  to  withstand  the  two  kinds  of  strain  must  either  result  in  an 
essentially  weak  gun  in  one  direction  or  the  other,  or  else  in  the  addition  of  a 
surplus,  if  not  a  useless,  amount  of  metal  to  accomplish  the  object  sought. 
Certainly  in  a  built-up  gun,  such  as  was  the  body  of  the  Mann  6.5-inch  rifle, 
there  exists  no  I'eason  for  such  a  complication  as  the  attempt  to  separate  the 
two  kinds  of  strains.  The  trial  was,  however,  a  distinct  test  of  the  breech 
mechanism. 

THE    YATES    BREECH    MECHAKISM. 

The  Yates  breech  mechanism  is  the  subject  of  a  patent  issued 
June  28.  1881,  to  Colonel  Yates,  a  retired  officer  of  the  Army.  It  is 
novel  in  principle  and  application,  and  consists  of  a  couple  of  con- 
cave clamps  (half  sections)  which,  when  closed,  embrace  the  breech 
of  the  gun  exteriorly,  and  are  intended  to  att'ord  longitudinal  support 
to  a  solid  head  gas  check  or  cartridge  case  of  whatever  nature  that 
may  be  used  within  the  breech  end  of  the  tube  for  the  actual  gas- 
sealing  device.  The  gas  check  ring  being  a  distinct  feature,  to  be 
operated  independently  of  the  breech-loading  device,  is  not  to  be 
understood  as  forming  a  part  of  it.  To  understand  this  distinction, 
without  intending  to  draw  a  parallel,  the  Yates  breech  mechanism 
takes  the  place  of  the  threaded  block  alone  in  the  slotted  screw 
system,  or  the  sliding  block  alone  in  the  Krupp  system.  A  parallel 
can  not  be  drawn,  because,  in  each  of  the  two  systems  named,  the 
block  forms  a  ready  means  for  supporting  or  supplementing  the  gas 
check  and  making  a  complete  automatic  breech-opening  device,  while 
in  the  Yates  plan  there  is  no  connection  between  the  gas  check  and 
the  rest  of  the  mechanism ;  the  breech  is  not  opened  or  closed  by  the 
operation  of  the  mechanism,  but  there  is  required,  in  addition,  a 
heavy  solid  head  gas  check,  which  must  be  placed  by  hand  in  the 
breech  end  of  the  tube  and  removed  in  the  same  way  for  every  round 
fired. 

The  "  clamps ""'  form  a  shell  or  envelope  for  the  entire  breech  of  the 
gun  divided  into  two  equal  parts  or  sections  which  meet  in  a  vertical 
plane  through  the  axis  of  the  gun.  The  front  of  each  clamp  is  hinged 
(in  common)  well  forward  on  the  reenforce  of  the  gun,  and  grooves 
or  shoulders  are  cut  circumferentially  on  the  interior  of  the  clamps 
which  when  the  sides  are  closed  hook  upon  corresponding  shoulders 
cut  around  the  reenforce  of  the  gun  and  afford  longitudinal  support 
to  the  clamps.  The  shell  formed  by  closing  the  clamps  comes  to  close 
bearing  over  the  breech  end  of  the  tube  to  support  the  gas  check. 
The  sides  open  to  uncover  a  little  more  than  the  diameter  of  the  bore 
at  the  breech.  The  opening  and  closing  is  done  by  means  of  a  lever 
attached  to  the  underside  of  the  breech  of  the  gun  and  pins  on  either 
clamp,  which  work  in  grooves  cut  in  the  lever.  When  closed,  the 
clamps  are  held  together  by  an  outside  latch  fastening  placed  above 


44  GUN    MAKING    IN    THE    UNITED   STATES. 

the  axial  line  of  the  giin.  This,  at  least,  was  the  original  arrange- 
ment; and  the  axial  line  was  occupied  by  a  firing  device  intended  to 
insert  a  pistol  cartridge  to  be  used  in  firing  the  charge,  but  the  latch 
fastening  broke  away  after  firing  a  few  rounds,  and  was  replaced  by 
a  locking  disk:  and  a  radial  vent  was  made  to  be  used  instead  of  the 
axial  vent. 

The  trial  of  a  gun  fitted  with  this  mechanism  was  made  by  the 
Board  for  Testing  Rifled  Cannon  at  Sandy  Hook  in  1885-86.  The 
gun,  made  at  the  cost  of  the  Government,  was  an  8-inch  rifle  converted 
from  a  10-inch  Rodman  smoothbore.  The  work  Avas  done  at  South 
Boston,  under  the  supervision  of  the  inventor.  The  breech  of  the 
smoothbore  gun  was  shaped  and  'bored  through,  and  the  muzzle 
lengthened  by  screwing  on  a  cast-iron  extension  piece.  The  whole 
was  lined  with  a  close-fitting  steel  (Nashua)  tube,  making  a  cham- 
bered gun  body  of  20  calibers  length  of  bore.  In  applying  the  ex- 
terior parts  of  the  breech  mechanism  to  this  gun.  the  outside  of-  the 
reenforce  was  necessarily  turned  off  to  provide  the  shoulders  for  the 
support  of  the  clamps.  To  complete  the  breech  closure — that  is,  to 
close  the  rear  end  of  the  bore  and  prevent  the  powder  gases  from  act- 
ing in  and  through  the  unsealed  joint  at  the  junction  of  the  clamps — 
the  inventor  designed  a  cartridge  case  of  bronze,  12  inches  total 
length  with  thin  walls,  and  heavy  solid  base  weighing  48i  pounds. 
This  case  was  tapered  on  the  outside  corresponding  to  a  seat  made  for 
it  in  the  chamber  of  the  gun  to  facilitate  withdrawal;  and  to  pro- 
vide against  sticking  a  slot  was  made  in  the  rear  of  the  tube  to  catch 
the  head  of  the  case  with  a  hand-extracting  tool.  This  case  was  in- 
tended to  be  used  for  repeated  firings,  but  was  necessarily  withdrawn 
after  each  round — the  work  being  done  by  hand  as  a  distinct  opera- 
tion of  opening  the  breech. 

The  gun  was  fired,  in  all  312  rounds,  when  it  burst  through  the 
body,  and  the  breech  mechanism  was  destroyed  by  the  rupture  of  the 
body.  Except  for  the  breaking  of  the  latch  in  the  early  firings,  there 
was  no  failure  of  the  breech-loading  device,  but  the  trial  developed 
its  unsuitability  as  a  breech  mechanism.  The  board  pronounced  the 
separation  of  the  gas  check  from  the  mechanism  to  be  a  "  clumsy, 
inconvenient,  and  objectionable  "  feature  as  proved  by  the  trial;  and 
found  that  the  *'  obturation  was  imperfect,"  the  gas  checks  "  not 
satisfactory  "  and  besides,  "  heavy  "  and  "  difficult  to  handle,"  and 
"  liable  to  serious  injury  from  accidental  dropping  or  striking  against 
objects  in  rapid  firing."  In  the  312  rounds  fired,  11  different  forms 
or  dimensions  of  gas  checks  were  tried  and  none  was  found  satis- 
factory. Xo  attempt  was  made  by  the  iuAentor  to  employ  a  gas 
check  which  would  not  require  the  awkward  handling  mentioned. 
As  a  consequence  of  this  serious  defect  the  Yates  breech  mechanism, 


GUN    MAKING    IN    THE    UNITED    STATES.  45 

as  api^liecl  to  guns  of  heavy  caliber,  is  not  at  present  a  practicable 
breech-loading  device. 

It  may  be  added,  I  think,  as  an  objectionable  feature  in  applying 
this  mechanism,  and  the  same  feature  is  even  more  pronounced  in  the 
Mann  system,  that  the  complete  truncation  of  the  body  directly  in 
rear  of  the  poAvder  chamber,  whereby  the  maximum  tangential  strain 
is  required  to  be  supported  so  near  the  end  of  the  gun  body,  renders 
these  S5^stems  liable  to  enlargement  and  very  obnoxious  deformation 
about  the  seat  of  the  gas  check.  It  also  introduces  a  weakness  against 
tangential  strain,  which  could  only  be  met  by  a  substantial  increase 
in  the  strength  of  the  breech  end  over  that  required  in  the  French  sys- 
tem at  least.  Krupp  does  strengthen  his  guns  at  this  place  by  shrink- 
ing on  an  additional  hoop.  Again  the  Yates  plan  necessitates  a  trim- 
ming down  of  the  reenforce  to  get  shoulders  for  the  clamps,  but  he 
might,  on  the  whole,  still  claim  a  margin  of  weight  saving  sufficient 
to  make  an  extra  heav}'^  gun  at  the  breech  end. 

The  result  of  this  trial  of  Colonel  Yates'  system  in  a  gun  of  8-inch 
caliber  is  an  example  of  the  difficulties  which  arise  with  an  increase 
of  the  caliber;  for  I  am  informed  that  the  device  has  been  found  to 
work  well  in  pieces  of  small  caliber,  such  as  yacht  guns. 

THE   SLOTTED    (INTERRUPTED)    SCREW   BREECH    MECHANISM. 

In  the  breech-loading  guns  to  be  subsequently  discussed — that  is, 
in  the  experimental  and  standard  types  recently  made  or  in  process 
of  construction,  after  the  plans  of  the  Armj?^  Ordnance  Department 
and  the  Navy  Bureau  of  Ordnance  in  the  United  States — the  system 
of  breech  mechanism  used  throughout  is  the  slotted  screw. 

This  system  owes  its  inception,  as  I  believe,  to  Chambers'  Ameri- 
can patent  of  1849  and  to  a  further  invention  patented  in  this  coun- 
try by  Schenkl  in  1853,  and  was  used  in  the  construction  of  6  guns 
made  at  Boston,  Mass.,  in  1855  for  the  British  Government  after 
designs  by  an  American  named  Castmann;  but  owing  to  clumsiness 
of  construction  these  guns  were  not  mounted."  The  system  was  then 
taken  up  in  France  and  gradually  developed  upon  a  working  plan. 
It  is  shown  and  described  in  the  Journal  des  Amies  Speciales  et  de 
I'Etat  Major,  V  Serie,  Tome  XII,  1864,  page  199 ;  VI  Serie,  Tome  II, 
1868,  page  161,  and  Armengaud's  Publication  Industrielle,  Tome 
XX,  1872,  page  297.  The  Journal  des  Armes  Speciales  for  1868 
states  that  these  guns,  of  a  caliber  of  12,  16,  24,  and  27  centimeters, 
had  been  adopted  by  the  French  for  the  navy,  as  well  as  for  forts 
and  coast  defense.^     As  regards  the  United  States,  there  was  then 

a  Holley's  Ordnance  and  Armor,  p.  608. 

6  See  also  Aide  Memoire  for  Officers  of  Artiller}%  chap.  1,  Paris,  1880.  (Pub- 
lislied  by  authority  of  the  minister  of  war.) 


46  GUN    MAKING    IN    THE    UNITED   STATES. 

no  room  for  such  development  in  the  face  of  our  (at  that  time) 
superior  armament  of  heavy  smoothbores.  The  system  was  officially 
recommended  for  trial  by  the  Heavy  Gun  Board  of  1872,  having 
been  especially  brought  to  the  attention  of  that  board  by  Lieutenant 
Michaelis.  of  the  Ordnance  Department.  That  board  also  recom- 
mended other  systems  of  breech  loading,  including  the  Krupp  sys- 
tem, the  tests  of  which  have  already  been  noticed.  The  slotted- 
screw  system  is  now  generally  used  in  native  gun  making  in  France, 
Italy,  England,  and  the  United  States.  In  France  it  is  now  mainly 
used  in  connection  with  the  gas  check  of  de  Bange,  who  in  1873  first 
used  an  expansible  pad  of  compressed  asbestos  and  tallow  for  the 
])urpose  of  transferring  the  pressure  of  the  mushroom  head  to  cer- 
tain metal  cups.  Avhich  were  thereby  expanded  radially  so  as  to 
check  the  gas.  Some  countries  still  use  the  Elswick  cup  and  the 
Broadwell  ring  to  a  certain  extent  in  connection  with  the  slotted- 
screw  breech  mechanism.  In  the  experiments  conducted  by  the 
Bureau  of  Ordnance  of  the  Navy  Department  in  1883  and  1884 
the  de  Bange  gas  check  (which  had  previously  been  used  only  for 
field  guns  in  France  and  elsewhere  in  Europe)  was  found  useless 
for  heavy  guns,  as  the  cups,  when  made  of  a  large  size,  lacked  elas- 
ticity and  stuck  so  badly  as  to  seriously  interfere  with  the  ^vorking 
of  the  breech  mechanism  in  opening  the  breech.  Much  better  suc- 
cess was  obtained  by  the  Davis  gas  check,  patented  in  1885.  which 
retained  the  asbestos  and  tallow  pad,  but  checked  the  gas  by  the 
radial  expansion  of  the  thin  edges  of  steel  disks  or  rings."  Hence 
the  term  "  French  breech  mechanism  "  is  applicable  only  in  a  general 
way  to  the  various  mechanisms  which  embody  the  slotted  screw 
as  used  in  the  United  States  and  elsewhere. 

The  Krupp  breech  mechanism  is,  of  course,  extended  in  use  to  a 
number  of  foreign  countries  where  sales  of  his  guns  are  made,  and 
it  has  been  adopted  in  manufacture  in  Eussia.  It  is  not  my  pur- 
pose here  to  discuss  the  relative  merits  of  these  Uxo  systems  of  breech 
mechanism.  It  may  be  doubted,  indeed,  if  there  is  much  room  to 
choose  between  them,  since  both  have  been  so  thoroughly  tested  and 
proved.  It  may  be  remarked,  however,  that  the  slotted-screw  system 
has  been  generally  received  by  gun  makers  in  choosing  between  one 
or  the  other  with  more  favor  than  the  Krupp,  and  probably  the 
principal  reason  for  this  is  that  the  Krupp  requires  a  forging  of 
larger  diameter  for  the  block-canying  cylinder  than  does  the  slotted 
screw,  which  may  even  be  attached  in  the  tube  forging  itself.  The 
size  of  the  required  forgings  for  12-inch  rifles,  it  will  be  recalled, 


"The  Gerdoni  gas  cheek.  ])a tented  m  1895,  is,  however,  more  nearly  perfect 
and  has  gradually  superseded  the  Davis.  In  this  device  the  ashestos  and  tallow 
pad  is  placed  between  resilient  steel  rings  of  peculiar  cross  section,  made  of 
about  0.02  inch  greater  diameter  than  that  of  the  gas-check  seat. 


GUN    MAKING   IN    THE    UNITED    STATES.  47 

and  the  inabilit}'  of  the  English  makers  to  produce  them  of  requisite 
quality,  was  what  stopped  the  extension  of  the  Krupp  system  in  our 
own  service.  A  possible  reduction  in  the  size  of  forgings  is,  of 
course,  always  a  desideratum,  and  especially  so  in  a  country  where 
the  manufacture  of  steel  forgings  is  a  comparatively  new  industry. 
It  undoubtedly  also  requires  the  best  quality  of  steel  to  carry  the 
Krupp  block,  and  where  a  cast-iron  body  is  used,  as  in  some  of  our 
present  constructions,  the  slotted-screw  block  is  a  necessary  adjunct. 
It  may  be  said,  then,  that  we  are  now  using  the  slotted-screw  system, 
because  it  is  one  of  the  only  two  that  have  been  proved  reliable  and 
satisfactory;  and  of  these  it  is  the  one  which,  on  the  whole,  is  best 
adapted  to  our  requirements  and  resources.  These  remarks  do  not 
apply  with  the  same  force  to  small  as  to  larger  calibers,  but  it  is 
expedient  to  have  a  uniform  system  for  all  calibers. 


IV. 

Cast- Iron  Rifles — Rodman,  Atwater,  and  AViard  Guns — 12-Inch 
Breech-Loading  Rifle,  Model  of  1883 — JSIerits  or  System  Dis- 
cussed. 

I  have  already  stated  that  the  trials  of  cast-iron  rifles,  pure  and 
simple,  were  practically  abandoned  in  the  United  States  in  1871. 
That  was  a  consequence  of  the  terrible  damning  that  cast-iron  guns 
received  at  the  hands  of  the  Select  Committee  on  Ordnance  in  1869 ; 
and  the  recommendation  of  the  Chief  of  Ordnance  two  years  later, 
that  no  cast-iron  rifles  should  be  made  for  service,  was  the  direct 
consequence  of  the  bursting  of  a  12-inch  Rodman  cast-iron  rifle  at  the 
twenty-seventh  round.  Up  to  the  time  when  the  subject  was  revived 
by  the  recommendation  of  the  Logan  committee,  in  1883,  fourteen 
years  had  elapsed  since  the  casting  of  the  last  cast-iron  rifle,  pure  and 
simple,  procured  by  the  War  Department.  This  gun  was  a  10-inch 
rifle  made  at  South  Boston,  in  1869. 

Seven  muzzle-loading  cast-iron  Rodman  rifles,  viz,  3  8-inch, 
1  10-inch,  and  3  12-inch,  were  procured  by  the  War  Department 
between  1861  and  1869.  Their  principal  dimensions,  weights,  and 
qualities  of  metal  were  as  follows : 


Caliber  of 
gun. 


Made  at— 


Thickness  of  walls 

Length  of  , 

-  bore  In     Overcham- 
calibers. 


ber  maxi- 
mum. 


At  muzzle 
minimum. 


8-inch 
8-inch 
8-inch 
10-inch 
12-inch 
12-inch 
12-inch 


Fort  Pitt,  1862 

South  Boston,  1865 

....do 

South  Boston,  1869 

Port  Pitt,  1861 

Fort  Pitt,  1868 

South  Boston,  1868 


15 

17.5 

17.5 

16.85 

14.0 

14.0 

14.0 


Calibers. 
1.5 
2.0 
2.0 
1.75 
1.5 
1.5 
1.5 


Inches. 


4.1 
4.0 
4.0 
5.5 
6.5 
6.B 
6.5 


Caliber  of 
gun. 


8-inch  .. 

8-inch  . . 

8-inch  . . 
10-inch  . . 
12-inch  . , 
12-inch  . . 
12-inch  . 


Weight 

of 

rifle. 


Character  of  rifling. 


Pounds.  .  *"• 

15,996  t  Polygroove 

22,160  I  For  grooved  projectile. 

22,220     Polvgroove 

40,700  '....."do 

52,005    do 

52,225    do 

51,980    do 


Physical  qualities  of 
metal. 


Tenacity.  !    Density. 


Pounds. 
30,416 
34, 625 
34, 505 
32, 600 
30,48C 
36, 744 
34, 166 


7.2886 
7.2930 
7.2980 
7.3063 
7.2260 
7.2903 
7.2%3 


48 


GUN    MAKING    IN    THE   UNITED    STATES. 


49 


The  8-inch  Fort  Pitt  model,  of  1862,  had  the  outside  lines  of  the 
10-inch  smoothbore,  giving  it  the  same  thickness  of  metal  as  the 
converted  muzzle-loading  rifles  afterwards  made  from  these  guns. 
The  two  8-inch  South  Boston  models,  of  1865,  were  special  designs 
prepared  b}^  Rodman,  and  were  of  heavj^  proportions,  having  2 
calibers  thickness  of  wall  in  the  reinforce  and  weighing  6,000  pounds 
more  than  the  first  model,  the  only  compensation  being  an  increased 
muzzle  length  of  2.5  calibers.  The  10-inch  rifle  had  a  thickness  of 
1.75  calibers  over  the  seat  of  the  charge  and  a  length  of  bore  less  than 
16  calibers,  dimensions  which  in  built-up  steel  guns  are  altered  to 
1.16  calibers  thickness  for  a  rifle  with  32  calibers  length  of  bore. 
The  12-inch  rifles  had  a  thickness  of  1.5  calibers  over  the  seat  of  the 
charge  and  14  calibers  length  of  bore.  The  physical  qualities  of 
metal  in  all  these  guns  was  fully  up  to  the  standards  of  tenacity  and 
density  now  attained,  or  that  can  be  attained  in  cast-iron  gun  metal. 

The  proof  of  these  guns  was  concluded  in  1871,  except  for  the  10- 
inch.     The  following  shows  their  endurance: 


Caliber  of 

Made  at— 

Average  full  charges. 

Number 
of  rounds 
endured. 

Trials 
con- 
cluded. 

Remarks. 

gun. 

Powder. 

Projectile. 

8-inch 

Fort  Pitt,  1862 

Pounds. 
15 
15 
15 
40 
55 
60 
64 

Pounds. 
150 
150 
150 
300 
500 

1,047 
80 

845 
70 

472 

1865 
1866 
1870 
1875 
1869 
1871 
1868 

Gun  burst. 

8-inch 

8-inch 

South  Boston,  1865 

do 

Do. 

Firing  suspended. 

10-inch.... 
12-inch 

South  Boston,  1869 

Fort  Pitt.  1861 

Gun  burst. 
Do. 

12-inch 

Fort  Pitt,  1868 

600                27 

Do. 

12-inch.... 

South  Boston,  1868 

624 

2 

Firing  suspended. 

The  maximum  powder  charge,  fired  from  the  12-inch  rifles,  was  70 
pounds.  Some  projectiles  of  675  pounds  weight  werealso  fired,  and 
a  few  of  700  pounds ;  but  the  charges  given  in  the  table  were  rather 
above  than  below  the  average  and  are  absurdh'  small  in  comparison 
with  those  of  the  present  day.  The  second  8-inch  gun  on  the  list 
w^as  rifled  with  five  lands,  separated  by  broad  grooves,  and.  the  pro- 
jectile was  grooved  to  take*  the  lands.  The  projectiles  used  in  the 
remainder  were  fitted  with  soft-metal  sabots,  chiefly  of  Parrott, 
Dyer,  and  Dana  patterns.  These  projectiles  were  the  best  pro- 
curable, and  the  trials  were  conducted  with  care — certainly  with  a 
strong  desire  on  the  part  of  the  proof  officers  to  make  the  best  of  the 
guns. 

The  pressures  recorded  to  have  been  endured  in  some  of  the  rounds 
fired,  exceeding  largely  as  they  do  the  amount  due  to  the  explosion 
of  a  charge  in  its  own  space,  are  something  remarkable  in  their 
way,  and  can  only  be  attributed  to  defective  methods  of  measure- 
ment. Here  we  find,  for  instance,  two  consecutive  rounds  fired  from 
an  8-inch  gun  on  the  same  day,  and  with  precisely  similar  charges, 

7733—08 4 


50  GUX    MAKING    IN    THE    UNITED   STATES. 

gave:  One  a  jDressure  of  90,000  pounds  with  1,154  feet  velocity,  and 
the  next  23,000  pounds  pressure  with  1,044  feet  velocity.  In  the 
records  of  these  pressures  we  find  figures  of  150,000  and  even  240,000. 
Some  of  the  pressures  were  measured  with  outside  pressure  gauges, 
and  the  result  of  balloting  of  the  interior  pressure  gauge  in  pro- 
ducing very  erroneous  measurements  was  not  appreciated.  In  1881 
Capt.  C.  S.  Smith  tried  the  experiment  of  dropping  tlie  Rodman 
pressure  gauge  complete  from  the  balcony  of  the  Western  Union 
tower  at  Sandy  Hook.  The  housing,  containing  the  knife,  etc., 
was  designedly  dropped  upon  a  stone  at  the  bottom  of  the  tower. 
The  height  was  such  as  to  make  the  velocity  of  fall  63  f.  s.  Even 
^with  this  small  velocity,  the  cuts  made,  on  striking,  corresponded 
in  one  trial  to  46,000  pounds,  and  in  the  second  to  35,500  pounds 
of  pressure  (Report  Chief  of  Ordnance,  1882.  p.  124).  Noble  and 
Abie's  experiments  gave  a  pressure  of  about  94,000  pounds  per  square 
inch  for  a  charge  of  powder  exploded  in  a  rigid  envelope  and  com- 
pletely filling  its  space.  The  action  in  the  chamJier  of  a  gun  can 
never  equal  that  in  a  rigidly  inclosed  space,  and  the  old  theory  that 
high  pressures  would  be  produced  in  a  gun  fired  with  a  projectile 
not  pushed  home  is  entirely  exploded  by  the  beneficial  results  obtained 
■  from  air  spacing. 

I  am  aware  that  the  bursting  of  the  guns  has  been  attributed  to 
the  breaking  up  of  the  projectiles,  wedging  of  bands,  uncertain  ]:)0w- 
ders,  and  other  causes  which  suited  the  interests  of  those  Avho  pro- 
pounded these  reasons,  but  I  believe  the  true  reason  to  lie  in  the 
frailty  of  the  guns  themselves.  In  the  8-inch  steel  rifle,  now  at 
Sand}'^  Hook,  for  example,  on  two  or  more  occasions,  shot  weighing 
about  300  pounds  have  been  broken  in  the  bore  by  the  shock  of  dis- 
charge; yet,  in  these  cases,  neither  was  there  any  marked  increase  of 
pressure,  nor  was  the  gun  in  the  least  injured.  And  again,  in  the 
trials  at  Annapolis,  two  loaded  shells  have  burst  within  the  muzzle 
of  the  new  steel  guns  without  detriment  to  the  guns. 

Another  12-inch  cast-iron  rifle,  tried  in  1867,  was  the  Atwater 
rifle.  In  this  gini  some  of  the  lands  were  removed  near  the  muzzle 
to  decrease  the  friction  of  the  projectile,  and  to  illustrate  some  other 
ideas  of  the  inventor.  The  gun  burst  at  the  thirtieth  fire,  the 
average  full  charge  used  being:  Powder  55  pounds,  and  projectile 
525  pounds.  And  there  was  also  Mr.  Norman  AYiard's  gun.  generally 
known  as  the  "  cart-whg^  "  gun.  which  burst  at  the  first  round. 

As  an  illustration  of  what  cast-iron  rifles  will  stand  when  hadly 
treated,  we  may  extract  the  four  of  this  class  which  were  included 
in  Wiard's  somewhat  notorious  experiments  at  Nut  Island,  1873-1875. 


GUN    MAKING   IN    THE   UNITED    STATES. 


51 


Nature  of  gun. 


IS-inch  Wiard  rifle,  new 
gun. 

15-inch  navy  Wiard  rifle 
converted  from  a  navy 
15-inch  .-smoothbore. 

15-inch  Wiard  rifle  con- 
verted from  15-inch 
Wiard  .smoothbore 
No.  1. 

11-inch  Wiard  rifle,  new 
gun. 


Charge. 


Kind  of  powder.    Weight 


Oriental  mam- 
moth. 


.do. 


Oriental  hex- 
agonal. 

Oriental  mam- 
moth, orien- 
tal rifle,  and 
Bickford  rifle. 


50 
110 

50 
180 

55 

70 

100 

50 
100 


Projectile. 


Kinds. 


^Wiard  conical . . 

Wiard  conical 
and  subcali- 
ber. 

1  Spherical  and 
Wiard  mitten. 


fWiard  conical, 
copper  ve- 
neered. 


I  No.  of 

rounds 

Weight,     tired. 


453 
492 


450 
529.5 


Remarks. 


Gun  burst. 
Do. 

Do. 

Do. 


The  Wiard  rifles  are  generally  admitted  to  have  been  destroyed 
by  the  use  of  excessive  charges  and  bad  projectiles,  yet  the  charges 
he  used  bear  no  comparison  with  those  now  required  to  be  used  in 
steel '  guns. 

We  have  now  brought  the  record  of  endurance  of  all  the  larger 
calibers  of  cast-iron  rifles,  pure  and  simple,  which  were  tested  up  to 
1883.  I  could  not,  if  I  would,  enter  into  the  details  of  the  experi- 
ments; that  there  may  have  been  mitigating  causes  for  some  of  the 
failures  one  would  be  rash  to  deny ;  but  the  general  merit  of  a  system 
is  to  be  judged  by  its  endurance  under  fire.  And  there  are  enough 
examples,  not  only  of  miscellaneous  cast-iron  rifles,  but  also  of  those 
oast  on  the  Rodman  plan,  in  the  preceding  records  to  enable  anyone 
to  decide  that  cast-iron  rifles,  pure  and  simple,  have  shown  a  very 
unstable  quality,  judged  bj^  their  own  da}'  and  generation.  The 
supposition  is  not  only  reasonable,  but  it  is  undeniable  that  the  Rod- 
man rifles  were  tested  with  due  exercise  of  care,  nor  was  there  any 
greater  varietj^  of  charging  than  was  demanded  by  the  period  to 
which  they  belong.  This  has  always  been  a  necessary  accompani- 
ment of  the  trial  of  experimental  guns,  and  is  a  very  marked  feature 
in  the  experiments  of  the  present  day.  Of  the  six  Rodman  rifles 
proved  for  endurance,  as  stated,  three  bore  a  good  record  and  three  a 
very  poor  record.  The  simple  conclusion  from  the  trials  of  the 
period  is,  that  cast-iron  rifles,  pure  and  simple,  were  proved  to  be 
distinctly  unreliable. 

12-INCH   BREECH-LOADING   CAST-IRON   RIFLE,  MODEL   OF   1883. 

The  design  of  this  gun  was  prepared  in  the  office  of  the  Chief  of 
Ordnance  in  common  with  all  those  representing  the  combined  cast- 
iron  and  steel  guns,  and  the  built-up  all-steel  guns  authorized  by  the 
act  of  1883. 

The  gun  is  a  12-inch  breech-loading  rifle,  weighing  54  tons  of 
2,000  pounds  each,  30  feet  total  length,  4f  feet  (56  inches)  across 
the  thickest  part  of  the  reinforce,  and  24  inches  across  the  muzzle. 
The  exterior  has  the  curved  outline  of  the  Rodman  model,  with  the 


52  GUN    MAKING    IN    THE    UNITED   STATES, 

thickness  of  the  wall  decreasing  toward  the  muzzle,  and  propor- 
tioned to  the  powder  pressure  to  be  withstood  in  the  different  sec- 
tions of  the  bore.  The  maximum  thickness  of  the  wall  surrounding 
the  chamber  is  21|  inches,  or  a  little  over  1|  calibers,  expressed  in 
terms  of  the  diameter  of  the  chamber;  the  thickness  over  the  seat 
of  the  shot  is  also  about  21  inches,  or  If  calibers,  and  at  the  muzzle 
(]  inches,  or  one-half  caliber.  The  bore  is  28  feet,  or  28  calibers,  in 
length,  of  which  the  powder  chamber,  13.5  inches  in  diameter,  oc- 
cupies nearly  .5^  calibers:  and  the  rifling  consists  of  60  lands  and 
grooves  0.06  of  an  inch  in  depth,  with  a  twist  increasing  from  one 
turn  in  135  calibers  at  the  origin,  to  a  uniform  twist  of  one  turn  in 
40  calibers,  which  covers  a  length  of  33  inches  next  the  muzzle.  The 
full  charge  is  265  pounds  of  brown  prismatic  powder  (density  of 
loading  0.84 ")  and  a  projectile  3  calibers  in  length  weighing  800 
pounds.  The  breech  mechanism  is  the  slotted  screw  system,  and  the 
steel  block  is  held  in  a  steel  sleeve  screwed  into  the  cast-iron  breech 
of  the  gun  to  the  depth  of  the  block  recess.  Excepting  the  parts  of 
the  breech  mechanism  and  this  sleeve,  the  gun  is  wholly  of  cast-iron 
and  is  in  one  piece,  cast  with  a  core  on  the  Eodman  plan  and  cooled 
from  the  interior  to  produce  initial  tension. 

The  gim  was  made  under  the  supervision  of  the  Ordnance  Depart- 
ment, by  contract  with  the  South  Boston  Iron  Works.  Eight  months 
were  occupied  by  the  contractors  in  preparing  for  and  making  the 
casting,  and  eighteen  months  in  all  in  finishing  the  gun.  The  casting 
was  made  breech  end  up,  with  a  riser  of  the  full  diameter  7  feet 
long.  Initial  tension  rings  taken  from  the  breech,  and  from  the 
muzzle,  and  cut  through  on  a  radius  in  the  usual  manner,  gave 
values  of  initial  tension  equaling  15,750  pounds  for  the  breech  end 
and  3,500  pounds  for  the  muzzle  end. 

The  firing  tests  were  conducted  at  Sandy  Hook  before  the  Board 
of  Testing  Kifle  Cannon.  The  report  of  that  board  upon  tests  made 
to  date  will  be  found  on  page  113,  Report  of  the  Chief  of  Ordnance, 
1886.    In  all,  137  rounds  have  been  fired : 

a  "  Density  of  loading  "  is  the  density  of  tlie  products  of  combustion  of  the 
powder  charge,  when  expanded  to  fill  the  powder  chamber,  referred  to  water  at 
a  standard  temperature  and  density,  as  unity.  Its  value  is  expressed  by  the 
quotient : 

.        f  1      1-         Weight  of  charge  expressed  in  pounds. 

Density  of  loading  =62.5  X  volume  of  chamber  space  expressed  in  cubic  feet. 


GUN    MAKING   IN    THE    UNITED    STATES. 


53 


Powder 
charge. 

Projectiles. 

Pounds. 
100 
200 
230 
150 
226 
246 
245 
266 
265 
265 

Pounds. 
700 

Do  .             

700 

Do 

700 

Grounds                     .                                                        

700 

2  rounds 

700 

Do                                                                                      

700 

1  round 

800 

3  rounds 

700 

41  rounds         .          .                                                                     

750 

800 

Of  these,  123  rounds  were  with  full  charges  of  powder,  and  79 
with  full  charges  of  powder  and  projectile.  The  average  pressure 
with  the  full  charges,  obtained  by  100  observations  (two  pressure 
gauges  being  sometimes  used  with  one  charge)  was  28,000  pounds 
per  square  inch,  and  a  fair  deduction  from  the  test  places  the  velocity 
to  be  obtained,  with  full  charges,  at  1,750  f.  s.  This  is  dependent, 
however,  upon  the  use  of  the  most  suitable  powder,  the  mak- 
ing of  which  is  known  to  be  a  very  difficult  operation.  The  single 
full  charge  fired  with  German  powder  gave  a  velocity  of  but  1,710 
feet  with  31,400  pounds  pressure.  The  best  results  were  obtained 
with  Du  Font's  N.  V.  powder,  of  which  five  lots  made  at  different 
times  were  tested,  and  gave  variations  (for  full  charges)  from  1,690 
f.  s.  with  25,325  pounds  pressure  to  1,809  f.  s.  with  34,000  pounds 
l^ressure.  This  last  was  the  highest  pressure  to  which  the  gun  was 
subjected  in  the  test,  excepting  one  round,  when  the  pressure  gauge 
was  dislodged  there  was  indicated  a  pressure  of  47,250  pounds, 
which  is  not  considered  reliable. 

Taking  the  average  result — charge  265  pounds,  projectile  800 
pounds,  pressure  28,000  pounds,  and  muzzle  velocity  1,750  feet — we 
find  that  the  power  of  this  gun  is  represented  by  a  muzzle  energy  of 
17,000  foot-tons,  nearly. 

The  erosion  of  the  bore  became  marked  before  the  fifty-first  round 
to  such  an  extent  "  as  to  make  star  gauging  very  difficult."  At  the 
ninety-sixth  round  the  erosions  became  pronounced,  and  increased 
rapidly  toward  the  end  of  the  test,  when  they  became  so  serious  as 
to  lead  the  board  to  conclude  that  it  would  be  unsafe  to  continue 
the  firing  with  the  gun,  but  it  was  thought  that  its  life  could  be 
prolonged  by  the  introduction  of  a  steel  lining.  The  star  gauging, 
which  appears  to  have  been  performed  under  difficulties,  shows  a 
general  enlargement  of  something  over  one-tenth  of  an  inch  near  the 
bottom  of  the  rifling  and  thence  decreasing  quite  uniformly  to  an 
inappreciable  quantity  at  the  muzzle.  In  the  chamber  the  maximum 
general  enlargement  appears  to  be  about  0.025  of  an  inch.  It  is 
difficult  to  give  a  clear  idea  of  the  extent  of  the  erosions  in  this  gun, 
especially  as  to  their  depth.  The  three  most  prominent  gutterings 
are  5^,  10|,  and  4|  inches  in  length,  running  nearly  parallel  to  the 


54  GUN    MAKING    IN    THE    UNITED   STATES. 

axis  of  the  gun  and  distributed  at  the  top  and  right  side  of  the  bore 
about  the  front  slope  of  the  powder  and  running  into  the  shot  cham- 
ber. The  impressions  indicate  flared  openings  having  a  depth  of 
about  0.15  of  an  inch,  but  can  not  show  the  depths  of  the  fine  extremi- 
ties of  the  cracks. 

Before  drawing  our  conclusions  from  this  new  addition  to  the  list 
of  cast-iron  rifles  that  have  been  proved  and  tested,  there  should 
be  several  points  considered  in  reference  to  current  methods  of 
manufacture  and  changed  conditions  of  service  due  to  the  introduc- 
tion of  slow-burning  powder.    It  is  claimed — 

1.  That  the  metal  now  made  is  better  than  ever  before. 

2.  That  the  ability  to  make  a  casting  with  the  core  extending 
through  the  portion  to  be  used  for  the  gun  body  and  casting  breech 
up  removes  all  the  objectionable  strains  incident  to  Rodman  castings 
of  muzzle-loading  smoothbores  and  makes  a  gun  with  the  best  con- 
dition of  metal  throughout. 

3.  That  castings  of  any  desired  size  and  length  can  be  made  to  give 
as  high  a  power  to  cast-iron  as  to  steel  guns. 

4.  That  existing  facilities  for  manufacture  or  means  ready  at  hand 
to  be  applied  permit  the  prompt  manufacture  of  a  large  number  of 
cast-iron  pieces  at  once — figures  variously  placed  at  soinething  like 
100  rifled  mortars  and  12  to  15  12-inch  rifles  per  year. 

5.  That  the  introduction  of  slow-burning  powders  has  made  the  use 
of  cast-iron  rifles  safe,  reliable,  and  economical. 

The  claim  for  superior  quality  of  metal  has  no  foundation  in  fact, 
as  may  be  made  apparent  to  anyone  who  will  acquaint  himself 
with  the  tests  of  metal  made  when  the  manufacture  of  cast-iron  guns 
was  a  large  and  extensive  business  and  the  tests  of  the  six  large 
castings  made  within  the  last  few  years. 

The  extension  of  the  core  barrel  through  the  gun  body  does  not 
remove  any  objections  heretofore  existing  to  the  Rodman  method  of 
casting,  first,  because  the  heavy  solid  breech  in  the  muzzle-loading 
guns  afforded  an  assistance  not  counterbalanced  by  the  local  strains 
occurring  at  the  junction  of  the  bore  and  base,  and,  second,  because 
the  principal  objections  taken  to  the  Rodman  method  are  not  with 
reference  to  the  strains  located  at  this  junction,  but  to  those  located 
along  the  barrel,  where  the  results  of  the  method  are  so  uncertain. 
The  method  of  casting  the  breech  up  has  many  objectionable  features, 
which,  probably,  counterbalance  any  gain  due  to  this  method,  but 
in  this  connection  I  may  mention  two  circumstances :  A  reason  for 
introducing  this  method  here  was  because  the  Italians  were  using  it ; 
yet  we  are  informed  now  that  it  has  been  abandoned  in  Italy  because 
it  does  not  give  sound  metal  in  the  breech,  where  the  greatest  strength 
of  the  gun  is  required.  And  the  third  casting  attempted  at  South 
Boston  for  the  12-inch  tubed  cast-iron  rifle,  made  in  this  way,  split 
longitudinally  while  still  in  the  pit. 


GUN    MAKING   IN    THE   UisriTED    STATES. 


55 


The  limits  of  size  and  length  of  casting  appear  to  have  been  aboui> 
reached  in  those  made  for  the  12-inch  rifles,  which  required  a  weight 
of  about  108  tons  of  metal  and  a  casting  some  40  feet  in  length  in  the 
rough ;  nor  are  existing  facilities  for  manufacture  such  as  would 
enable  any  considerable  number  of  cast-iron  rifles  to  be  finished  before 
we  could,  with  home  facilities,  inaugurate  a  steady  output  of  built-up 
steel  guns.  The  only  facilities  existing  at  present  in  this  country,  for 
making  long  and  heavy  gun  castings,  are  to  be  found  at  the  South 
Boston  Iron  AVorks.  AAHiat  has  been  done  there  is  shown  by  the  fol- 
lowing record  of  the  time  required  to  turn  out  6  castings  recently 
procured  from  that  company,  all  i-equiring  rough  finishing  only, 
except  the  first  on  the  list : 


No. 


Nature  of  casting-. 


12-inclf  cast-iron  rifle, 

simple. 
Boriy  forl2-inch  tubed 

rifle: 
First  casting 


Second  casting . 


Third  casting. . 
Fourth  casting 


Date  of  order. 


Sept.  24,1883 


Sept.  24, 1883 


Body  for  12-inch  hoop- 
ed" and  tubed  rifle. 

Body  for  10-inch  wire- 
wrapped  rifle. 

Mortars. 

Body  for  12-inch  muz- 
zle-loading rifled 
mortar. 

Body  for  12-inch 
breech-loading 
rifled  mortar. 


Sept.  24, 1883 
Sept.  24,1883 

Sept.  24,1883 
May   l.'i,1886 


Date  of  cast- 
ing. 

May 

6,1884 

July 

9,1884 

Dec. 

23, 1884 

* 

Oct. 

16, 1886 

Apr. 

5, 1886 

Oct. 

31, 1884 

Mar. 

28, 1884 

Mar. 

1,1884 

July 

30, 1886 

Apr.     1,1885 


Mar.  31,1885 
Sept.    1,1884 


Apr.   29,1884 


Sept.  30, 1886 


Remarks. 


Cast  breech  up  with  riser  at 
breech  7  feet  long. 


Flask  gave  way  and  metal 
deposited  in  bottom  of  pit. 

Cast  breech  down,  lower 
portion  of  flask  surround- 
ed bydry  brick  wall  pack- 
ed around  with  sand  in 
pit.  Casting  broke  across 
in  several  places  in  lathe. 

Cast  breech  up  and  ruptured 
longitudinally  in  pit. 

Cast  breech  up.  Apparently 
sound  casting. 

Cast  breech  down  with  riser 
at  muzzle  18  inches  long. 


Casting  delayed  in  procur- 
ing proper  grade  of  iron 
and  making  trial  cylinders 
for  test. 


"  Not  completed  .Tune  20,  1886.  when  contra;t  expired  by  limitation. 

The  simple  cast-iron  rifle.  Avith  which  no  accident  occurred,  was 
eight  months  in  casting  and  eighteen  in  finishing;  and  the  five  cast- 
ings ordered  September  24,  1883,  were  not  all  made  at  the  expiration 
of  two  years  and  six  months.  The  founders  certainly  had  very  hard 
luck  with  the  casting  for  one  gun.  which  was  only  made  at  the  fourth 
trial,  and  my  purpose  in  calling  attention  to  these  matters  is  simply 
to  show  the  time  that  has  actually  been  occupied  in  such  work  and  the 
risk  and  difficulties  which  attend  an  attempt  to  make  heavy  cast-iron 
rifles.  The  West  Point  Foundry  could  undertake  the  casting  of  the 
short  bodies  required  for  the  hooped  mortars,  but  with  this  exception 
I  believe  no  other  establishment  than  the  South  Boston  Iron  Works 
has  at  present  any  proper  facilities  for  the  work.    The  hooping  of  the 


^6  GUN    MAKING    IN   THE    UNITED   STATES. 

mortars  with  steel  will  delay  the  output  but  little  and  will  give  what 
has  been  proved  to  be  a  suitably  strong  construction.  That  12-inch 
cast-iron  rifles  may  even  be  cast  as  long  as  may  be  required  for  modern 
usage  is  much  to  be  doubted  in  view  of  the  experience  quoted,  but 
the  added  length  would  not  give  the  power  of  steel  guns  because  of 
the  limitations  of  pressure  imposed  upon  the  cast-iron.  Again,  to 
increase  the  length  of  a  cast-iron  gun  entails  a  large  increase  of  the 
weight  and  cost,  noting  that  in  1865,  when  General  Rodman,  in 
revising  the  model  of  his  8-inch  cast-iron  rifle  of  1862,  imposed  an 
additional  weight  of  6,000  pounds  to  gain  2.5  calibers  length  of  bore. 

That  the  introduction  of  slow-burning  powders  has  made  it  safe 
to  use  cast-iron  rifles  is  doubtful,  and,  besides,  is  only  half  stating  the 
question.  They  may  be  safe  if  the  pressures  are  kept  low  enough,  but 
with  a  pressure  as  high  as  28,000  pounds  produced  by  a  slow-burning 
powder  their  endurance  would  be  an  uncertain  factor.  This  pressure 
would  work  the  metal  well  up  to  the  point  of  rupture,  while  in  steel 
guns  the  work  of  the  metal  is  within  its  elastic  limit  and  less  than 
half  its  limit  of  rupture.  The  new  12-inch  cast-iron  rifle  has  with- 
stood an  average  pressure  of  28,000  pounds,  including  a  number  of 
somewhat  higher  pressures  for  a  sufficient  number  of  rounds  to  dem- 
onstrate its  ability  to  withstand  such  pressures  and  to  entitle  it  to  be 
classed  as  a  safe  medium-power  gun  for  the  caliber.  This  much  must 
be  conceded,  and  it  may  be  anticipated  that  equally  good  guns  can 
be  reproduced,  but  past  experience  of  the  uncertain  strength  of 
cast-iron  rifles  does  not  warrant  the  assumption  that  it  would  be 
safe  to  count  upon  such  a  result  as  a  constant  product  of  manufacture. 
In  addition  to  this,  the  slow-burning  powder  is  very  erosive  in  its 
action,  and  of  all  the  metals  that  might  be  used  to  form  the  bore  of 
a  gun,  cast  iron  is  probably  the  most  easily  eroded.  We  have  a  good 
example  of  this  effect  in  the  12-inch  cast-iron  rifle,  which  began  to 
show  marked  erosion  about  the  fiftieth  round,  while  the  8-inch  steel 
gun  shows  none  after  100  rounds. 

A  businesslike  view  of  the  problem — and  it  has  been  sufficiently 
investigated  by  both  figures  and  firings — will  show  that  a  built-up 
forged-steel  gun,  giving  17,000  foot-tons  muzzle  energy  at  each  round, 
is  a  cheaper  investment  than  this  12-inch  cast-iron  rifle  giving  the 
same  energy;  that  is.  the  greater  endurance  of  the  steel  gim  will 
enable  it  to  continue  to  deliver  such  shots  enough  longer  than  the 
cast-iron  gun  to  more  than  make  up  the  difference  in  the  original  cost 
of  the  guns.  And  beyond  this,  the  difference  of  cost  is  all  in  favor 
of  the  much  lighter  piece — the  steel  gun — for  transportation,  hand- 
ling, and  emplacement.  This  in  itself  is  enough  to  establish  the 
superiority  of  the  steel  gun,  but  it  is  not  the  most  important  consid- 
eration, which  is,  comparatively  speaking,  that  the  steel  gun  is  safe 
and  the  caM-iron  gun  is  unsafe.     It  is  not  necessary  to  go  abroad 


GUN    MAKING   IN    THE   UNITED    STATES.  57 

for  a  confirmation  of  this  statement;  it  can  rest  upon  a  comparison 
of  the  records  of  cast-iron  and  built-up  steel  rifles  made  at  home. 
It  is  a  good  confirmation,  however,  to  know  that  the  practice  of  the 
rest  of  the  world  proves  the  same  thing. 

The  question  whether  cast-iron  rifles  shall  be  or  shall  not  be  made 
rests  with  Congress.  If  they  are  to  be  made,  let  them  be  ordered  at 
once  in  the  quantities  determined  upon,  for  there  is  certainly  no  need 
for  further  experiments  in  this  line.  Let  us  sincerely  hope,  however, 
that  any  action  taken  for  their  procurement  will  not  interfere  with 
equally  prompt  action  toward  procuring  a  full  supply  of  built-up 
forged-steel  guns;  to  fail  in  this  respect  would,  in  my  humble 
opinion,  be  the  poorest  sort  of  economy. 

The  ability  which  the  officers  of  the  Ordnance  Department  have 
shown  in  designing  so  powerful  a  cast-iron  rifle  as  the  one  lately 
proved  is  an  earnest  of  their  desire  and  capacity  to  carry  out  what- 
ever Congress  may  direct.  Had  the  12-inch  cast-iron  rifle  been  made 
after  a  design  presented  to  the  Logan  committee,  that  was  to  fire  150 
pounds  of  powder  with  700-pound  shot  and  give  a  muzzle  energy  of 
but  10,000  foot-tons  instead  of  the  17,000  foot-tons  procured  in  the 
design  actually  used,  but  little  interest  would  attach  to  a  discussion 
of  its  merits  here  or  elsewhere. 


V. 

Combined  Cast  Iron  and  Steel  Guns — Rifled  Mortars — Breech- 
Loading  Rifles — AVire  Guns. 

Including  the  rifled  mortars,  there  are  three  different  types  of  this 
construction  in  hand  at  the  present  time,  viz,  a  12-inch  breech-load- 
ing rifle,  mainly  of  cast  iron,  but  lined  with  a  steel  tube  inserted  from 
the  rear,  and  forming  about  one-half  the  length  of  the  bore ;  a  12-inch 
breech-loading  rifle,  with  cast-iron  body,  strongly  reen forced  by  a 
double  row  of  steel  hooping  extending  from  the  breech  to  a  distance 
forward  of  the  trunnions — the  trunnions  themselves  forming  part  of 
one  of  the  hoops — and  a  steel-tube  lining,  as  in  the  first  gun ;  and  two 
12-inch  rifled  mortars  alike  in  general  construction,  but  one  is  muzzle- 
loading  and  the  other  breech-loading. 

12;-IXCH   RIFLED  MORTARS.   MUZZLE  AND  BREECH   LOADING. 

These  are  short,  rifled  pieces  intended  for  high-angle  fire,  and 
especially  adapted  for  the  defense  of  seaports.  They  throw  a  very 
heav}^,  elongated  shell,  containing  a  large  bursting  charge,  to  a 
distance  of  5  miles  with  facility.  The  weight  of  shell  is  from  610  to 
625  pounds,  and  its  fall  is  sufficient  to  pierce  about  8  inches  of  armor. 
In  the  Russian-Turkish  war  a  6-inch  mortar  firing  from  shore  dis- 
abled two  ironclads. 

The  arrangement  of  the  pieces  on  shore  will  be  made  in  groups  of 
16,  as  is  proposed,  placed  in  sunken  batteries,  and  so  trained  that  any 
desired  number  of  the  pieces  in  the  battery  can  be  fired  in  the  same 
line  of  direction  against  a  single  ship.  The  most  serious  question 
raised  respecting  the  employment  of  rifled-mortar  fire  has  been  in 
regard  to  its  accuracy.  Their  employment  in  groups  will  do  much  to 
overcome  this  difficulty  by  greatly  increasing  the  chances  of  hitting, 
and  the  problem  of  getting  a  very  good  degree  of  accuracy  from  a 
single  piece  is  one  that  the  gun  makers  will  not  allow  to  remain 
unsolved.  Its  solution  seems  to  lie  in  the  use  of  breech-loading  pieces, 
and  we  have  just  commenced  the  proof  of  a  mortar  of  this  kind  at 
Sandy  Hook  which  promises  the  best  results. 

The  first  experimental  rifled  mortar — 12-inch  muzzle-loading — was 
completed  in  1884,  and  proved  1885-86  by  the  Board  for  Testing  Rifled 
Cannon.  The  reasons  leading  to  the  adoption  of  the  muzzle-loader 
58 


GUN    MAKING   IN    THE   UNITED    STATES. 


59 


for  the  first  experimental  type  were  because  it  was  then  thought  that 
the  old  method  of  loading  from  the  muzzle  would  be,  on  the  whole, 
best  adapted  to  such  short  pieces  as  combining  simplicity  and  cheap- 
ness, together  with  less  care  and  attention  required  in  service  as  com- 
pared with  the  breech-loader.  This  piece  has  been  fired  403  rounds, 
and  is  considered  amply  strong  for  service.  A  range  of  8,260  yards 
(540  yards  short  of  5  miles)  was  obtained  with  this  muzzle-loading 
mortar,  firing  a  charge  of  52  pounds  of  powder  and  610  pounds 
projectile  at  an  elevation  of  45°,  the  flight  being  good  and  forty-one 
and  one-half  seconds  in  duration.  Examples  of  the  accuracy  of  fire 
obtained  with  full  and  half  charges  at  different  angles  of  elevation, 
are  given  in  the  table  herewith : 


Probability  of  striking 

vessel  330'  long   bv 

60'  broad. 

Powder 

Elevation. 

Number  of 

Mean 

charge. 

rounds. 

range. 

Vessel  nor- 

With keel 

mal  to 

lying  in 

plane  of 

plane  of 

fire. 

fire. 

Pounds. 

Deprees. 

Yards. 

Per  cent.       Per  cent. 

26 

28 

5 

3, 427 

35.3 

98.75 

26 

28 

10 

3,490 

38 

9y 

26 

60 

5 

3,321 

16.5 

66.6 

26 

60 

8 

3,260 

13                  44. 04 

52 

28 

4 

6,935 

18                  61. 66 

52 

28 

10 

7,142 

12.5              41.32 

The  best  record  of  accuracy  given  is  a  target  of  10  shots,  range 
3,490  3^ards,  showing  a  percentage  of  99  hits  for  100  shots  on  the  deck 
of  a  vessel  330  feet  long  and  60  feet  wide,  lying  with  keel  in  the  plane 
of  fire,  and  38  with  the  vessel  lying  normal  to  the  plane  of  fire.  And 
again  at  7,000  yards  range,  for  a  target  of  four  shots,  the  percentage 
of  hits  was  62  for  the  first  position  of  the  vessel  and  18  for  the  second 
position.  It  was  found  necessary,  in  the  firing,  to  use  sabots — the 
Arrick  pattern  was  found  to  be  the  best — prepared  w  ith  care  to  give  a 
certain  degree  of  sensitiveness,  and  there  also  appeared  some  advan- 
tages in  using  them  of  different  degrees  of  sensitiveness  for  full  and 
half  charges.  These  defects  of  material  required  for  service,  together 
with  the  generally  unsatisfactory  degree  of  accurac}^  and  lack  of  uni- 
form steadiness  in  the  flight  of  the  shell,  led  the  Department  to  manu- 
facture a  breech-loading  mortar,  which,  on  firing  for  the  first  time  a 
few-  days  since,  gave  very  satisfactory  results.  With  a  powder  charge 
of  65  pounds  and  projectiles  625  pounds  the  measured  range  was 
9,385  yards,  or  5^  miles.  Nine  preliminary  rounds  were  fired,  and  the 
flight  of  the  projectiles  was  true  and  clean. 

In  general  design  these  mortars  show  a  short  rifled  piece  of  about 
9  calibers'  length  of  bore.  The  muzzle-loading  mortar  Aveighs  13^ 
tons,  and  the  breechloader  is  three-fourths  of  a  ton  heavier.  The 
latter  is  fitted  with  the  slotted  screw  block  and  breech  mechanism 


60  GUN    MAKING    IN    THE    UNITED   STATES. 

embodying  a  new  and  special  design  of  retracting  gear.  In  gen- 
eral construction  the  two  pieces  are  nearly  alike.  The  principal 
f)art  is  a  cast-iron  body,  which  forms  about  two-thirds  of  the  whole 
weight.  On  the  outside  of  this  two  rows  of  steel  hoops  are  shrunk 
on,  extending  from  the  breech  forward  over  about  two-thirds  of 
the  length  of  the  piece.  The  trunnions  are  forged  as  part  of  one 
of  the  steel  hoops,  which  is  shrunk  on  in  the  same  way  as  the  others. 
Preparatory  to  making  the  first  mortar  an  experimental  compound 
cylinder — a  counterpart  of  the  body  of  mortar  around  the  chamber — 
was  made  by  shrinking  two  of  the  lot  of  hoops  upon  a  cylinder  of 
the  iron  for  the  purpose  of  testing  the  metals  and  verifying  the 
shrinkages  computed  for  the  construction  of  the  mortar  itself.  In 
this  case,  as  in  several  other  similar  ones  tried  with  the  different 
types  of  guns — combined  cast-iron  and  steel,  cast-iron  wire-wrapped, 
and  all-steel  guns — the  results  of  these  experimental  constructions 
confirmed  in  a  highly  satisfactory  manner  the  results  anticipated  by 
theory  and  the  application  of  standard  formulas. 

These  rifled  mortars  are  apparently  made  verv  heavy  in  proportion 
to  their  length.  The  necessity  for  this  arises  from  the  heavy  weight 
of  projectile  used,  and  because  they  are  also  subjected  to  a  pressure 
which  may  easily  reach  30.000  pounds  per  square  inch,  for  it  is  nec- 
essary to  use  a  relatively  quick-burning  powder.  The  ratio  of 
weight  of  projectile  is  onh^  1  to  50.  Cast  iron  is  a  cheap  metal, 
and,  if  properly  strengthened,  appears  well  adapted  to  use  in  these 
pieces  to  make  up  the  weight.  A  number  of  persons,  actuated  gen- 
erally, no  doubt,  by  good  motives,  but  principally,  as  I  must  assume, 
because  they  have  not  carefully  examined  into  the  question,  have 
wished  to  make  these  mortars  of  cast  iron  alone.  The  reason  why 
it  is  not  best  to  do  this  is  because  the  simple  cast  iron  would  give 
no  assurance  of  safety  in  the  service  of  the  piece.  With  the  pres- 
sures used  in  these  pieces,  to  repeat  what  has  been  said  before,  the 
cast  iron  would  be  strained  to  near  its  limit  of  rupture.  By  shrink- 
ing on  the  two  rows  of  hoops — one  row.  unless  the  hoops  were  very 
heavy,  would  not  be  sufficient — the  strain  upon  the  cast  iron  when 
the  piece  is  fired  is  reduced  to  somewhat  less  than  one-half  of  what 
it  would  be  if  there  were  no  hoops.  The  hoops,  therefore,  are  shrunk 
on  to  give  such  a  factor  of  safetj^  as  all  structures  demand,  and  none 
need  this  factor  of  safety  more  than  do  guns.  Added  to  this  the  cer- 
tainty of  good  metal  in  the  hoops  surrounding  the  cast  iron  where 
the  strain  is  greatest  relieves  a  constant  source  of  anxiety  regarding 
the  unsoundness  of  heavy  cast-iron  castings.  We  know  that  the 
hoops  will  hold  and  that  their  presence  will  make  up  for  a  greater 
or  less  degi-ee  of  imperfection  in  the  cast  iron.  The  strength  of  these 
mortars  based  upon  strains  that  lie  within  the  elastic  limit  of  the 
steel  hoops  and  about  equal  for  the  cast  iron  to  those  which  fail 
to  produce  an   appreciable  permanent  set  of  the  metal,   is   nearly 


GUN   MAKING   IN    THE   UNITED    STATES.  61 

27,000  pounds  per  square  inch.  That  is  to  say,  the  elastic  strength 
of  the  mortar,  banded  with  two  rows  of  hoops,  just  about  equals 
the  average  strain  anticipated  in  service. 

12-INCH   BREECH-LOADING  RIFLES. 

Neither  of  the  large  rifled  guns  of  this  system  have  yet  been  deliv- 
ered, as  has  already  been  noted.  The  tubed  gun  has  reached  the 
stage  preparatory  to  the  insertion  of  the  tube  in  the  cast-iron  body, 
and  the  hooped  and  tubed  gun  is  completed,  but  can  not  be  accepted 
until  the  necessary  legislation  has  been  passed. 

The  trial  of  the  tubed  gun  may  be  looked  forward  to  with  some 
interest,  as  it  may  prove  to  afford  a  sufficient  increase  of  strength 
to  make  a  safe  medium-power  gun.  principally  of  cast  iron,  and  at 
the  same  time  remedy  the  fault  found  in  the  erosion  of  a  simple 
cast-iron  rifle  firing  large  charges  of  slow-burning  powder.  Both 
guns,  the  hooped  and  tubed  one  especially,  belong  to  the  transition 
period  from  cast  or  wrought  iron  to  the  built-up  steel  gun.  But 
because  we  haA'^e  delayed  the  adoption  of  all-steel  guns  in  this 
country  to  so  late  a  period  and  take  them  up  not  as  an  experi- 
mental but  as  an  established  sj^stem,  we  may  well  avoid  the  neces- 
sity of  expending  time  and  money  on  the  further  purchase  of  these 
composite  guns,  which  ruled  for  a  number  of  vears  in  France  and 
Italy. 

The  tubed  gun  was  originally  designed  to  have  the  steel  tube 
wrapped  with  wire,  and  in  that  design,  as  does  also  the  present  design 
of  the  hooped  and  tubed  gun,  represents  an  alternative  system  of 
gun  construction  belonging  to  a  period  four  j^ears  since.  This  was 
before  we  had  made  any  substantial  progress  in  the  manufacture 
of  gun-steel  forgings  in  this  country,  and  those  designs,  offering  as 
they  did  a  satisfactory  amount  of  strength  for  the  anticipated 
medium  power  of  the  guns,  were  brought  forward  to  meet  emer- 
gencies and  home  facilities.  They  also  offered  the  advantage  of 
giving  orders  to  our  steel  makers  for  steel  forgings  of  a  size  adapted 
to  the  early  stages  of  that  industry,  arid  enabled  them  to  acquire 
experience  looking  toward  the  manufacture  of  larger  forgings,  such 
as  were  figured  in  the  built-up  all-steel  guns  presented  for  manufac- 
ture at  the  same  time.  Meantime  it  became  necessary  to  go  abroad 
to  purchase  the  larger  forgings  (tube  and  jacket)  for  the  steel  guns. 

The  tubed  rifle,  as  it  is  now  to  be  made  with  a  simple  steel  tube, 
will  have  the  same  general  dimensions  and  weight  as  the  12-inch 
cast-iron  rifle  already  described.  The  tube  does  not  extend  through 
to  the  breech,  but  is  cut  off  at  the  rear  at  the  base  of  the  powder 
chamber,  and  the  breechblock  is  held  in  a  steel  sleeve  screwed  into 
the  cast  iron,  so  that  the  longitudinal  strain  will  be  supported  by  the 
cast-iron  body  alone. 


62  GUN    MAKING    IN    THE    UNITED   STATES. 

The  hooped  and  tubed  rifle  is  two  calibers  shorter  in  the  bore  than 
the  preceding  and  will  weigh  53  tons.  This  gun,  built  up  b}'  the 
successive  shrinkage  of  the  cast-iron  on  tube  and  two  rows  of  hoops 
on  the  outside,  is,  when  compared  with  a  simple  cast-iron  rifle,  or  even 
the  tubed  rifle,  an  exceedingly  strong  construction.  The  making  of 
the  gun  itself,  in  pursuance  of  a  systematic  plan  adopted  by  the  Ord- 
nance Department  for  built-up  gun  construction,  was  preceded  by 
an  experimental  construction  embodying  a  complete  section  of  the 
gun  through  the  reinforce — that  is,  a  comiDOund  cylinder  forming  a 
counterpart  of  the  gun  section.  The  section  of  cast-iron  cylinder 
used  in  this  was  cut  from  the  body  of  the  gun  casting,  and  the  steel 
parts  were  of  similar  material  to  the  forgings  made  for  the  gun. 
The  objects  accomplished  by  this  means  were  a  verification  of  the 
shrinkages  calculated  for  the  gun  and  a  practical  test  of  the  metals 
on  the  same  scale  as  the  gun  itself.  This  gun  will  safeh^  support  an 
interior  pressure  of  38,000  pounds  per  square  inch  without  exceeding 
the  elastic  limit  of  the  metals,  and  thus  affords  at  least  double  the 
assurance  of  safety  to  be  derived  from  a  simple  cast-iron  gun,  which, 
under  some  10,000  pounds  less  pressure,  is  strained  to  near  the  limit 
of  rupture  of  the  metal,  and,  although  a  shorter  gun  than  the  cast- 
iron  rifle,  it  will,  with  the  same  chamber  space,  afford  more  power 
than  that  gun,  and  with  safety.  A  large  charge  of  powder  may  be 
used  with  a  greater  density  of  loading,  and  higher  pressures,  with 
higher  velocities,  even  with  the  same  weight  of  shot,  will  be  attain- 
able, and  will  give  an  increased  energy. 

The  half  tube  is  inserted  with  a  slight  longitudinal  shrinkage,  in 
addition  to  the  circumferential,  the  object  of  this  being  to  insure 
a  close  joint  in  the  bore  where  the  steel  tube  ends  and  the  bore  passes 
into  the  cast  iron.  The  tube  is  also  continued  through  to  the  breech, 
being  threaded  and  screwed  into  the  cast-iron  body  for  a  length  of 
26  inches  next  the  breech.  This  portion  forms  a  reinforce  on  the 
tube  and  admits  of  sufficient  thickness  of  wall  to  cut  the  thread  for 
the  breechblock  in  the  tube  itself.  The  screw  connection  between  the 
tube  and  the  cast-iron  body  transmits  the  longitudinal  strain  to  the 
body.  The  steel  parts  of  this  gun  make  up  a  little  more  than  two- 
fifths  of  the  total  weight  of  the  piece. 

WIRE    GUNS. 

Two  of  these  guns  made  after  designs  presented  byJDoctor  Wood- 
bridge  are  partly  constructed.  The  work  was  under  way  at  the  Water- 
town  Arsenal,  but  was  suspended  in  June,  1886,  through  failure  of 
appropriation  for  its  continuance.  On  one. of  the  guns,  a  10-inch, 
breech-loading,  wire-wrapped,  cast-iron  rifle,  the  wire  winding  is 
completed,  and  the  gun  has  yet  to  be  finished  on  the  outside,  bored. 


GUN   MAKING   IX    THE    UNITED    STATES.  63 

rifled,  and  fitted  with  breech  mechanism.  The  steel  forgings  and  wire 
for  the  construction  of  the  second  gun — a  10-inch  breech-loading  steel 
rifle,  longitudinal  bars,  wire  wrapped — have  been  procured,  but  no 
portions  of  the  gun  have  yet  been  put  together. 

The  10-incli  wire-wrapped  cast-iron  rifle  will  have  28  calibers 
length  of  bore  and  w^eigh  29  tons.  The  cast-iron  body  weighs  17 
tons,  and  is  wrapped  with  0'M5  square  wire  with  slightly  rounded 
corners,  applied  (for  the  most  part)  with  a  uniform  tension  at  the 
rate  of  41,000  pounds  per  square  inch  of  section  of  wire  for  nearly 
one-half  the  length  of  the  gun,  beginning  near  the  breech.  The  muz- 
zle half  of  the  cast-iron  body  is  not  covered.  A  steel  trunnion  band 
is  shrunk  on  the  outside  of  the  ware,  and  the  portion  of  wire  in  front 
of  the  band  is  covered  by  a  steel  sleeve,  also  shrunk  on,  which  will 
transmit  the  thrust  of  the  trunnion  band  to  another  steel  hoop  shrunk 
on  the  cast-iron  body  and  backed  up  by  a  key  ring  screwed  on  cold. 
In  the  section  surrounding  the  powder  chamber  the  thickness  of  cast- 
iron  is  9.835  inches  and  of  wire  5.49  inches.  This  gun  may  be  ex- 
pected to  stand  with  safety  an  interior  pressure  of  36,000  pounds  per 
square  inch,  which  is  computed  to  be  the  pressure  necessary  to  produce 
a  tangential  stress  of  19,200  pounds  per  square  inch  on  the  cast-iron 
metal  at  the  inner  surface  of  the  chamber.  An  interesting  experi- 
ment embodjdng  an  investigation  of  the  initial  tension  in  the  cast 
iron,  and  the  effect  produced  by  winding  on  the  wire,  the  efficacy  of 
the  soldering  proposed  for  the  wire,  and  for  general  information  re- 
garding the  construction  of  the  gini,  was  conducted  at  the  arsenal 
preparatory  to  commencing  work  on  the  gun.  It  comprised  the  con- 
struction of  a  complete  section  of  the  gun,  and  is  described  in  Notes 
on  the  Construction  of  Ordnance  No.  38,  to  which  reference  has  been 
made  in  discussing  the  subject  of  initial  tension  in  cast-iron  guns. 
An  important  result  of  this  experiment  was  the  apparent  inadequacy 
of  the  soldering  process,  arising  from  the  failure  of  the  solder  to 
thoroughly  penetrate  the  mass.  The  soldering,  although  it  would 
afford  some  assistance  in  the  longitudinal  resistance,  was  intended 
especially  to  hold  the  wires  together  to  prevent  slipping  in  a  cir- 
cumferential direction  when  the  gun  is  fired.  Another  object  was  to 
prevent  the  wire  from  unraveling  if  a  strand  were  cut  on  the  ex- 
terior by  a  hit  from  a  shot  or  other  accident.  A  full  account  of  the 
construction  of  this  gun,  as  far  as  progi'essed,  including  a  discussion 
of  the  strains  by  Lieutenant  Crozier,  is  published  in  the  Report  of 
the  Chief  of  Ordnance  for  1886,  page  359  et  seq.  The  wire-winding 
machine  used  in  this  work  is  also  of  Doctor  Woodbridge's  invention. 
The  type  of  wire-wrapped  cast-iron  rifles  was  commended  by  the  Getty 
Board  as  a  cheap  construction,  coming  within  the  manufacturing 
facilities  of  the  country.  The  design  presented  is  not  considered  by 
its  advocates  as  at  all  presenting  the  highest  type  of  wire  gun. 


64  GUN    MAKING    IN    THE    UNITED   STATES. 

The  10-inch  steel  gun.  longitudinal  bars,  wire-wound,  is  intended 
to  reprensent  such  a  type.  The  design  presents  a  gun  weighing  22 
tons,  with  30  calibers  length  of  bore.  The  wire  winding  extends 
from  the  breech  to  the  muzzle.  The  tube  is  of  steel,  and  extends  en- 
tirely through  the  gun,  so  that  the  breechblock  screws  directly  into 
it.  One  of  the  most  important  features  of  the  gim  is  the  means  to 
be  provided  to  give  longitudinal  strength.  This  consists  of  a  casing 
of  longitudinal  bars  or  staves  made  to  form  a  cylinder  fitting  the 
tube  over  about  one-half  its  length  from  the  breech,  and  is  connected 
indirectly  at  its  front  end  with  the  trunnion  band  and  at  its  rear  end 
with  the  breechblock.  The  steel  tube  and  trunnion  hoops  for  this 
gun  were  procured  from  "WHiitworth.  The  bars  and  the  wire  for  both 
guns  are  of  home  manufacture.  The  steel  bars  and  billets  were  pro- 
cured principally  from  the  Otis  Iron  and  Steel  Company,  Cleveland, 
Ohio.  The  bars  were  cold  rolled  at  the  works  of  Jones  &  Laughlin, 
Pittsburg,  Pa.,  and  the  wire  drawn  at  Trenton,  N.  J.,  at  the  works  of 
the  Trenton  Iron  Company. 

The  Nav3'  Department  has  in  hand  a  6-inch  steel  tube  wire-wrapped 
gun.  It  is  partly  comj)leted,  but  no  work  has  been  done  upon  it  for 
some  time  past. 

The  tests  of  these  gims  when  completed  will  best  enable  an  opinion 
to  be  formed  of  their  merits.  The  advantage  of  wire  wrapping  on 
the  cast-iron  body  over  steel  hooping  is  not  apparent,  as  the  cast-iron 
body  could  be  sufficiently  strengthened,  for  the  limit  of  its  endur- 
ance, by  the  application  of  steel  hoops,  which  would  besides  obviate 
the  danger  to  be  apprehended  from  any  accident  which  might  cut  and 
loosen  the  outer  strands  of  wire.  Wire  guns,  however  meritorious 
may  be  the  designs  projected,  and  even  the  results  of  firing  tests  of  a 
number  already  constructed  in  other  countries,  have  as  yet  scarcely 
passed  the  experimental  stage.  Their  object  being  to  enable  the  use 
of  excessive  charges  the  difficulty  of  making  them  a  serviceable  con- 
struction is  enhanced.  The  mechanical  difficulties  of  the  construction 
enter  in  the  attempt  to  make  a  compact  and  serviceable  structure  in 
combining  the  parts  designed  to  resist  the  two  kinds  of  strain.  There 
are,  however,  able  advocates  of  wire  gun  construction.  It  appears  also 
that  continuous  endeavors  are  being  made  to  perfect  the  system,  and 
it  is  not  my  intention  to  discredit  trials  with  this  or  any  other  system 
which  embodies  as  much  promise  of  success  as  does  the  wire  gun  con- 
struction. 


VI. 


Steel-Cast  Gr>'S. 

At  the  last  session  of  Congress,  b}'  act  approved  March  3,  1887, 
the  Sinn  of  $20,000  Ava^  apjiropriated  for  expenditure  by  the  Navy 
Department  for  the  purchase  and  completion  of  three  steel-cast, 
G-inch,  high-power  rifle  camion  of  domestic  manufacture,  one  to  be 
of  Bessemer,  one  of  open-hearth,  and  one  of  crucible  steel.  In 
response  to  proposals,  bids  were  recently  received  for  two  of  these 
castings  to  be  furnished  rough  turned  and  bored,  from  which  the 
finished  guns  are  to  be  made.  The  Pittsburg  Steel  Casting  Company 
furnished  the  bid  for  a  Bessemer  casting,  and  the  Standard  Steel 
Casting  Company  that  for  the  open-hearth,  or  Martin-Siemens,  cast- 
ing. The  crucible  steel  casting  was  not  bid  for.  The  main  features 
of  the  specifications  in  the  bids  are  as  follows : 


Casting  rough  bored  and 
turned. 

Cost. 

Elastic 
limit. 

Tensile 
limit. 

Ultimate 
elonga- 
tion. 

Reduc- 
tion of 
area. 

Weight 
of  fin- 
ished 
gun. 

Length 
of  fin- 
ished 
gun. 

Bessemer  steeL . 

Dollars. 
3,300 
5,300 

Pounds. 
40, 000 
30,000 

Pounds. 
80, 000 
70,000 

Per  cent. 

7 

10 

Per  cent. 

7 
5 

Pounds. 
11,000 
15,000 

Inches. 
193. 53 

Ooen-hearth  steel 

193. 53 

These  guns  when  finished  will  be  required  to  fire  a  projectile  weigh- 
ing 100  pounds  with  a  muzzle  velocity  of  not  less  than  2,000  f .  s.  and 
to  stand  the  statutory  test  prescribed  by  the  act  of  July  26,  1886, 
which  for  navy  guns  has  constituted  a  test  of  10  rounds  fired  as 
rapidly  as  possible.  The  dimensions  of  the  steel-cast  guns  proposed 
are  suited  to  reproduce  the  interior  dimensions  of  the  6-inch  Navy 
forged-steel  guns,  so  that  in  order  to  produce  the  effect  required,  the 
charge  of  powder  will  be  from  48  to  52  pounds,  and  the  pressure 
probably  not  less  than  15  tons.  In  weight  and  exterior  dimensions 
the  Bessemer  casting  will  closely  approach  the  navy  gun,  while  the 
open-hearth  casting  will  make  a  heavier  gun  by  4,000  pounds.  The 
price  asked  for  these  rough-finished  castings  will,  when  the  guns  are 
finished  and  fitted,  make  the  cost  of  one  exceed  and  of  the  other 
not  greatly  less  than  the  total  finished  cost  of  the  6-inch,  built-up, 
forged-steel  guns  manufactured  at  the  Washington  Navy- Yard  from 
materials  entirely  of  home  production. 

-  7733—08 5  65 


66  GUN   MAKING   IN   THE    UNITED   STATES. 

The  physical  qualities  of  the  metal  bear  a  poor  comparison  with 
those  obtained  in  forgings,  as,  for  example,  taking  a  piece  of  some- 
what larger  caliber,  the  forgings  for  tube  of  the  T-inch  steel  how- 
itzer furnished  the  War  Department  by  the  Cambria  Company 
gave,  elastic  limit,  47,250  pounds;  tensile  limit,  92,750  pounds;  ulti- 
mate elongation,  21.1  per  cent;  reduction  of  area,  29  per  cent. 

We  are  not  informed  of  the  methods  proposed  to  be  used  in  the 
manufacture  of  these  castings  and  can  only  await  the  trial  of  the 
guns  to  form  conclusions.  They  mark  the  first  step  in  an  attempt  to 
establish  the  manufacture  of  steel-cast  guns  in  this  country,  and  our 
great  manufacturing  facilities,  together  with  the  constant  advances 
now  being  made  in  the  art  of  steel  casting,  may  enable  us  to  over- 
<?ome  man}'  of  the  difficulties  encountered  in  like  attempts  already 
made  in  other  countries.  And  as  this  is  the  first  step  in  a  matter 
which,  if  ever  successful,  will  probabh'  require  a  number  of  years  to 
extend  itself  to  the  successful  production  of  guns  of  12-inch  caliber 
and  upward,  it  is  perhaps  unreasonable  to  cavil  at  the  number  and 
comparatively  diminutive  size  of  the  guns  now  to  be  made.  The  trial 
of  one  G-inch  steel-cast  gun  of  a  given  make  may  prove  something  in 
regard  to  6-inch  guns,  but,  in  the  face  of  past  experience  and  present 
widespread  distrust  of  the  suitability  of  unforged  (or  unpressed) 
steel  guns,  can  do  little  to  predicate  what  result  will  be  obtained 
with  larger  castings. 

Another  potent  necessity  for  making  the  small  calibers  at  present 
appears  to  lie  in  the  capacity  of  the  steel  works  for  making  such 
castings,  for  there  is  no  doubt  but  that  a  special  plant  must  yet  be 
provided  for  making  the  larger  calibers  of  steel-cast  guns.  This  is 
one  of  the  items  of  expense  which,  combined  with  others,  Avill  prob- 
ably make  the  cost  of  production  of  a  gun  of  large  caliber  quite  as 
expensive  if  made  in  this  way  as  if  made  of  forgings  and  built  up. 
The  amount  of  metal  used  for  the  hollow  castings  made  or  attempted 
for  12-inch  cast-iron  rifles  was  about  240,000  pounds,  or  somewhat 
more  than  double  the  weight  of  the  finished  piece.  The  rule  of 
double  the  weight  holds  good  in  heavy  steel  castings.  Taking,  for 
example,  a  12-inch  steel  gun,  the  heaviest  casting  required  for  a 
built-up  forged-steel  gun  of  this  caliber  is  40  tons,  to  be  cast  in  the 
simplest  form  of  a  solid  ingot.  This  gives  a  rough-finished  forging 
of  14.5  tons  weight,  also  less  than  half  that  of  the  casting.  Applying 
these  rules  to  the  massive  casting  of  a  12-inch  steel-cast  gun,  the 
Aveight  of  casting,  if  made  hollow,  would  exceed  100  tons,  and  if 
made  solid  would  exceed  120  tons  at  the  least  estimates  allowable. 
And  for  this  massive  casting  a  special  plant,  flask,  and  all  the 
adjuncts  must  be  provided.  If  we  go  to  IG  inches  caliber,  the  com- 
parison is  84  tons,  as  the  heaviest  casting  for  the  forged-steel  gun 
iigainst  not  less  than  250  tons  for  the  steel-cast  gun.     Considering 


GUISr    MAKING   IN"    THE   UNITED    STATES.  67 

the  extreme  difficulty  of  making  sound  steel  castings  of  even  a  few 
tons  weight  at  the  present  time,  how  long  may  it  be  before  such 
castings  as  these  can  be  manipulated?  For  guns  of  such  caliber, 
then,  it  ma}^  be  said  the  steel-cast  system  is,  from  present  lights  and 
practices,  a  question  for  the  future. 

The  feasibility  of  making  castings  for  steel-cast  guns  up  to  10-inch 
caliber  (weight  of  casting  about  60  tons)  seems  within  the  reach  of 
appliances  that  might  be  readily  provided,  but  that  such  guns  or  even 
smaller  ones  can  be  made  of  good  sound  material  possessing  the 
requisite  physical  qualities  to  compare  in  strength,  endurance,  and 
power  with  built-up  forged  steel  guns  of  the  same  caliber  can  not  be 
conceded.  To  even  approach  this  it  would  be  indispensable  that  the 
steel-cast  gun  should  be  made  with  a  proper  degree  of  initial  tension. 
The  Rodman  method  of  casting  has  been  proposed,  but  whether 
intende<i  to  accomplish  the  introduction  of  initial  tension  or  not  has 
not  been  made  quite  clear  by  its  advocates.  The  slow  process  of  cool- 
ing incident  to  this  method  would  cause  the  formation  of  large  weak 
cr3'stals  in  the  castings,  and  apparently  recognizing  this  the  advocates 
of  the  method  have  proposed  to  remove  all  the  initial  tension  strains 
by  an  after  annealing.  This  would,  moreover,  appear  to  be  a  Avise 
precaution,  inasmuch  as  this  method  of  casting  is  so  uncertain  in 
cast  iron  and  would  be  much  more  so  in  steel,  with  its  greater  shrink- 
age and  liability  to  crack  from  internal  strains  in  the  casting.  If, 
then,  the  Rodman  method  is  not  used  for  the  j^urpose  of  introducing 
initial  tension,  the  hollow  casting  is  certainly  a  bad  form,  as  proved 
by  Wliitworth's  trials  and  tribulations  with  it.  The  unsoundness 
found  in  the  center  of  a  solid  cast  ingot  is  in  this  case  only  trans- 
ferred to  the  middle  of  the  walls  of  the  gun — a  result  in  every  way 
bad,  and  which  no  subsequent  treatment  can  correct. 

The  idea  embodied  in  the  making  of  steel-cast  guns,  viz,  that  steel 
in  a  relatively  weak  condition  is  abundantly  strong  for  the  work 
required  of  a  gun  is  a  decided  step  backward.  The  work  now 
required  of  a  gun  can  not  be  measured  by  the  days  of  Rodman  and 
Wade.  A  steel-cast  gun  is  essentially  not  a  gun  of  equal  strength, 
and  no  addition  to  the  massiveness  of  the  structure  can  make  it  so, 
but  only  add  to  the  inherent  difficulties.  The  greatest  gun-making 
establishment  in  the  world  has  gone  through  all  these  stages  and 
found  this  to  be  true.  After  years  of  trial  with  the  massive  (forged) 
construction  Krupp  turned  to  making  built-up  guns. 

The  method  of  procuring  initial  tension  in  steel-cast  guns  seems 
to  be  that  followed  by  the  Otis  Iron  and  Steel  Company,  who  pre- 
sented a  steel  cylinder  to  the  War  Department  for  test  in  1884.  The 
cylinder  was  cast  solid,  bored,  and  during  three  successive  heatings  in 
a  furnace  cooled  from  the  interior.  The  initial  tension  thus  produced, 
tried  by  the  obscure  method  of  cutting  a  full  ring,  was  indicated  to 


68  GUX    MAKING    IX    THE    VXITED   STATES. 

be  10,000  pounds  per  square  inch.  The  tests  of  specimens  of  metal 
taken  from  different  parts  of  the  cylinder,  which  was  5  feet  long, 
24  inches  outside  and  6  inches  interior  diameter,  did  not,  however, 
warrant  the  making  of  a  steel-cast  gvni. 

It  may  be  stated  as  a  fundamental  principle  that  to  make  a  gun 
safe  to  withstand  repeated  firings  without  undue  enlargement  or 
rupture  it  should  possess  sufficient  elastic  tangential  strength  in  its 
walls  to  meet  the  strain  due  to  the  pressure  of  the  powder  gases,  and 
it  is  desirable  to  have  a  considerable  margin  above  this.  The  elastic 
resistance  of  a  simple  cylinder — that  is,  one  of  neutral  metal — 
expressed  in  terms  of  pressure  of  the  bore  can  not  equal  the  elastic 
strength  of  the  metal  (determined  by  specimen  tests).  If  we  call 
P  the  pressure  and  6  the  elastic  limit  of  the  material,  the  elastic 
t agential  strength  of  a  simple  cylinder  maj^  be  determined  by 
the  formula." 

in  which  Hj  and  R^  stand  for  the  exterior  and  interior  radii.     From 

this— 

If  Ri  =  2Ro,  thickness  of  wall  =  i  caliber  ;  P=0.5  6^ 
If  Ri  =  3Ro,         ''         ^'     "     =  1       "       ;  P=0.63  e 
If  Ri=4Ro,         "         "     "     =  H     "       ;  P=0.68  e 
If  Ri  =  5Ro,         "  "     "     =  2       "       ;  P=0.71  6 

A  value  of  $  equal  to  35,000  pounds  may  be  considered  at  least  not 
too  low  for  the  metal  to  be  had  in  a  steel-cast  gun.  This  gives  the 
simple  gun  an  elastic  resistance  of  23,800  pounds  if  the  wall  be  1.5 
calibers  thick,  and  24,850  pounds  if  the  wall  be  2  calibers  thick,  and 
is  certainly  far  from  satisfactory  in  a  gmi  which  will  be  subjected  to 
pressures  of  36,000  pounds  or  more. 

This  leads  to  an  examination  of  how  much  the  elastic  resistance  of 
the  gun  may  be  improved  by  the  introduction  of  a  proper  state  of 
initial  tension.  An  investigation  of  this  question  is  given  in  Appen- 
dix B.  The  physical  properties  of  the  metal  assumed  for  the  discus- 
sion are: 

p  =  Force  corresponding  to  safe  compression  of  metal  =  40,000 
0=      ''  "  "         extension  "     =35,000 

The  example  is  for  an  8-inch  gun  in  which  the  thickness  of  wall  is 
taken  equal  to  1^  calibers  for  the  section  in  front  of  the  chamber. 
This  is  in  excess  of  the  present  designs  of  8-inch  built-up  guns.  Re- 
garding the  liability  of  the  gun  to  fail  under  either  radial  compres- 
sion or  tangential  extension  of  the  bore,  the  limit  of  its  resistance 

o  Formula   (17)   Notes  on  the  Construction  of  Ordnance,  No.  35. 


GUN    MAKING   IN    THE   UNITED    STATES.  69 

becomes  in  the  first  case  38,156  pounds  per  square  inch,  but  if  we 
admit  that  the  bore  may  be  extended  tangentially  to  the  elastic  limit 
the  resistance  would  be  49,130  pounds  per  square  inch.  This  assumes 
that  the  correct  state  of  initial  tension  has  been  produced,  a  prac- 
tical question  which  rests  in  the  hands  of  the  manufacturer  to  solve. 
But  taking  even  the  failing  limit  under  radial  compression  we  find 
that  the  introduction  of  a  proper  initial  tension  would  increase  the 
elastic  resistance  over  that  of  a  simple  cylinder  some  14,500  pounds. 
It  appears  that  a  thickness  of  wall  equal  to  1.5  calibers  is  well  adapted 
to  the  problem,  as  it  gives  nearly  the  same  value  for  the  pressure 
which  would  cause  the  failing  limit  under  radial  compression  to  be 
reached  and  that  which  would  produce  an  equal  extension  of  the  metal 
throughout  the  thickness  of  the  wall  in  the  state  of  action.  A  purpose 
of  the  discussion  is  also  to  call  attention  to  what  appears  to  be  the 
best  practical  method  of  experimentation  in  order  to  obtain  a  knowl- 
edge of  the  actual  state  of  initial  tension  introduced  by  any  given 
process  of  manufacture  that  may  be  adopted.  With  this  knowledge 
obtained  and  a  careful  record  kept  of  the  method  of  treatment  it 
might  be  hoped  to  reproduce  the  same  result  in  successive  castings. 
A  fundamental  part  of  the  oj)eration  would  be  to  cause  the  tangential 
compression  of  the  metal  at  the  surface  of  the  bore  to  be  brought 
approximately  at  least  to  the  elastic  limit  of  compression  of  the  metal 
(in  this  case  assumed  to  be  40,000  pounds  per  square  inch).  This  is 
indispensable  to  getting  the  best  resistance  that  the  gun  will  offer. 


VII. 

Built-up  Forged  Steel  Guns — Progress  Made  in  their  Construc- 
tion— Pneumatic  Dynamite  Torpedo-Gun — Commercial  Value 
of  Gun-Forging  Plant — Gun   Shops — Conclusions. 

This  type  of  gim,  as  we  make  it  to-day,  is  the  embodiment  of  Pro- 
fessor Treadwell's  clear  idea  of  a  gun  of  equal  strength,  as  announced 
in  1843 ;  of  Chambers'  mechanical  ideas  of  breech  mechanism  and  of 
hooping  in  layers  with  the  hoops  of  each  layer  breaking  joints, 
patented  in  1849;  of  Rodman's  elegant  exposition  of  the  benefit  of 
procuring  initial  tension  in  a  gun,  published  in  the  same  year,  and 
finally  of  Professor  Treadwell's  extension  of  this  principle  to  the 
application  of  layers  of  cylinders  or  hoops  in  making  a  built-up  gim." 
All  these  men  were  Americans,  and  were  pioneers  in  announcing 
these  principles,  which  cover  about  all  the  fundamental  ones  of  the 
built-up  gun.  These  ideas  went  on  their  travels  and  took  root  in 
Europe,  where  money  is  spent  on  guns  and  defenses,  and  where 
slowly,  but  surely,  side  hj  side  with  forged  or  pressed  steel,  there  was 
developed  at  a  comparatively  recent  date  the  modern  type  of  built-up 
forged  steel  gun,  which  now  undoubtedly  holds  an  unrivaled  place. 
The  French  worked  up  the  breech  mechanism,  and  Vavasseurs'  prac- 
tical application  of  Treadwell's  first  idea  has  introduced  the  jacket 
piece  which  performs  the  double  function  of  affording  the  means  to 
secure  the  requisite  amount  of  longitudinal  strength,  and  at  the  same 
time  properly  assists  the  remaining  layers  in  resisting  the  tangential 
strains.  The  responsible  officers  of  the  Government  realized  some 
years  since  what  was  taking  place,  and  like  sensible  folk  concluded 
that  it  would  be  best  to  expend  the  public  funds  upon  the  best  and 
the  only  good  article  in  the  market.  The  Navy  Bureau  of  Ordnance, 
backed  up  by  the  Naval  Committees  of  Congress  with  liberal  appro- 
priations, has  been  successful  in  doing  this;  the  Ordnance  Depart- 
ment of  the  Army  has  received  appropriations  sufficient  only  to  make 
and  test  some  experimental  guns.  Both  have  used  their  utmost 
legitimate  efforts  to  make  the  production  of  built-up  forged  steel 

a  I  am  aware  that  Blakely's  claim  to  this  is  in  dispute  with  Professor  Tread- 
well's. Both  patents  were  taken  out  in  the  same  year  (3855),  and  Blakely  at 
the  same  time  announced  the  principle  of  "  varying  elasticity,"  but  this  latter 
finds  no  special  application  to-day,  and  there  is  little  doubt  but  that  Professor 
Treadwell's  claim  to  originality  in  this  matter  is  a  just  one. 

70 


GUN   MAKING   IN    THE   UNITED    STATES.  71 

guns  entirelj'^  a  matter  of  home  manufacture,  and  have  studied  for 
themselves  the  principles  of  mechanical  engineering  involved. 

What  I  shall  have  to  say  about  these  principles  will  give  an  outline 
of  the  studies  of  this  nature  which  the  officers  of  the  Army  Ordnance 
Department  have  made,  and  the  knowledge  which  they  have  acquired 
by  care  and  practice  in  the  construction  of  experimental  ginis,  and  in 
efforts  to  improve  the  quality  of  the  steel  forgings.  I  will  not  be 
understood  as  disclaiming  our  great  indebtedness  to  foreigners  for 
the  money  and  invent iAeness  and  skill  they  have  expended  in  estab- 
lishing the  superiority  of  the"  built-up  forged  steel  gun;  but  we  did 
not  import  mechanical  engineers  to  teach  us  how  to  build  these  guns, 
and  we  in  the  Army  hope  very  soon  to  be  put  in  the  present  condition 
of  the  Navy — that  is,  to  have  placed  at  our  disposal  a  domestic  supply 
of  the  material  required  for  making  them.  We  already  know  that 
our  steel  makers  are  capable  to  make  the  very  best  grades  of  gun 
steel,  arid  it  has  been  shown,  as  in  the  case  of  the  Navy  Bethlehem 
contract,  that  the  only  requisite  to  placing  an  order  for  steel  forgings 
in  this  country  is  that  Congress  shall  appropriataa  reasonable  amount 
for  their  purchase. 

The  amount  of  oil-tempered  and  annealed  gun  steel  forgings  which 
the  Ordnance  Department  has  procured  from  home  manufacturers, 
since  1883,  somewhat  exceeds  200  tons,  Avhich  has  been  suppliect  by 
the  Midvale  Steel  Company  and  the  Cambria  Iron  and  Steel  Works. 
A  list  of  the  principal  forgings.  showing  when  and  where  made,  etc., 
is  given  in  xVppendix  A.  The  forgings  were  procured  for  the  follow- 
ing purposes  in  built-up  gun  construction: 

I.  For  experimental  purposes  incideut  to  the  making  of  guns. 

(a)    Shrinkage  and  specimen  tests  of  steel  hoops  to  determine  qualities  of 

metal  best  suited  for  purposes  of  gvui  construction  based  on  method 

of  treatment  in  manufacture  (1S8:>)  (1). 
(&)   Construction  of  a  compound  cylinder  representing  a  full  section  through 

the  reinforce   (around  chamber)   of  8- inch  breech-loading  steel  rifle 

(1885)  (2). 

(c)  Construction  of  same  character  for  12-inch  muzzle-loading  rifled  mortar, 

cast-iron  body  (?>). 

1.  Notes  on  the  Construction  of  Ordnance,  No.  25. 

2.  Notes  on  the  Construction  of  Ordnance,  No.  32. 
.3.  Report  of  the  Chief  of  Ordnance,  1885.  page  209. 

4.  Report  of  the  Chief  of  Ordnance,  1885,  pages  277  and  314. 

5.  Report  of  the  Chief  of  Ordnance,  1885,  pages  317  and  321. 

6.  Report  of  the  Chief  of  Ordnance,  18SG,  page  22. 

7.  Notes  on  the  Construction  of  Ordnance,  No.  39. 
S.  Notes  on  the  Construction  of  Ordnance.  Xo.  41. 

(d)  Construction  of  same  character  for  12-iuch  hooped  and  tubed  breech- 

loading  rifle,  cast-iron  body  (4). 

(e)  Effect  of  contact  with  molten  cast-iron,  and  temporary  exposure  to  a 

high  furnace  heat,  upon  the  qualities  of  oil-tempered  steel  (5). 


72  GUN    MAKING    IN    THE    UNITED    STATES. 

I,  For  experimental  puri>oses  incident  to  the  uialvins;  of  gnns — Continued. 

(f)  Frictional  resistance  to  longitudinal  separation  of  finished  steel  cylin- 
ders, shrunk  one  over  the  other  as  in  gun  construction  (G). 

(fir)  Shrinkage  and  specimen  tests  of  forged  steel  trunnion  hoop  to  deter- 
mine qualities  of  metal  throughout  the  forgings  (1886)  (7). 

ill)  Examinations  of  the  strains  produced  by  oil  treatment,  and  the  effect 
of  after  annealing  in  removing  injurious  strains  from  the  forgings 
(1887)  (8). 

II.  For  the  manufacture  of  guns. 

51  complete  sets  of  forgings  for  .3.2-inch  breech-loading  field  guns,  steel. 
1  complete  set  of  forgings  for  5-inch  breech-loading  siege  rifle,  steel. 
1  complete  set  of  forgings  for  7-inch  breech-loading  rifled  howitzer,  steel. 
50  complete  sets  of  forgings  for  8-inch  muzzle-loading  converted  rifles, 

including  tubes,  breech  cups  and  muzzle  collars. 
110  forged    (rolled  or  hammered)    steel  hoops  for  8  and   10  inch  breech- 
loading  rifles,  steel,  and  two  12-inch  rifled  mortars,  and  one  12-inch 
hooped  and  tubed  breech-loading  rifle,  cast-iron  bodies. 

In  order  to  complete  the  experimental  guns  rtuthorized  by  the  act 
of  1883,  the  Department,  being  unable  to  procure  in  the  United  States 
forgings  of  the  size  required,  has  purchased  from  Sir  Joseph  ~\Miit- 
worth  &  Co.  the  folloAving,  which  have  all  been  delivered,  viz :  Five 
tubes  (one  8-inch,  two  10-inch,  and  two  12-inch  short  tubes),  two 
jackets  (one  8-inch  and  one  10-inch)  and  five  trimnion  hoops  (one 
8-inch,  two  10-inch,  and  two  12-inch).  Since  these  orders  were  filled 
the  Midvale  Steel  Works  has  demonstrated  its  capacity  to  make 
forged  trunnion  hoops  as  large  as  12-inch,  having  made  one  of  these 
for  the  12-inch  breech-loading  mortar,  and  has  also  succeeded  in  pro- 
ducing a  complete  set  of  forgings,  tube,  jacket,  and  forged  trunnion 
hoop  included,  for  an  8-inch  steel  rifle,  the  qualities  of  metal  being 
satisfactory  throughout. 

The  progress  made  in  the  manufacture  of  built-up  forged-steel  guns 
to  date  is  as  follows : 

Twenty-six  3.2-inch  breech-loading  field  guns,  steel,  have  been  completed ;  the 
forgings  for  25  additional  gims  are  on  hand,  and  their  manufacture  has  been 
commenced  at  the  Watervliet  Arsenal. 

One  5-inch  breech-loading  siege  rifle,  completed  and  in  prepai-ation  for  test. 

One  7-iuch  breech-loading  rifled  howitzer,  completed  and  in  preparation  for 
test. 

One  8-iuch  breech-loading  rife,  steel :   tested  up  to  101  rounds. 

One  8-inch  breech-loading  rifle,  steel ;  forgings  procured  and  manufacture 
commenced  at  Watervliet  Arsenal. 

One  10-inch  breech-loading  rifle,  steel;  forgings  procured  and  manufacture 
commenced  at  Watervliet  Arsenal. 

If  one  is  disposed  to  ask  avIij-  no  more  than  this  has  been  accom- 
plished they  may  be  respectfully  referred  to  the  Appropriations  Com- 
mittees o£  Congress,  who.  for  two  years  pa-t.  have  deemed  it  wise  to 
make  no  appropriations  for  the  armament  of  fortifications,  and  this 
has  so  crippled  o])erations  that  the  Department  has  been  compelled 


GUX    MAKING    IN    THE    UNITED    STATES. 


73 


to  discharge  even  the  .small  force  of  skilled  employees  at  the  proving 
ground,  and  has  been  able  to  accomplish  almost  nothing  in  the  way  of 
completed  guns,  except  for  the  smallest  caliber.  Its  officers,  however, 
have  devoted  this  time  of  waiting  to  a  close  and  careful  study  of  the 
best  methods  to  be  pursued  in  the  manufacture  of  gun-steel  forgings, 
and  of  matters  i)ertaining  to  gun  construction ;  and  the  extensive  and 
thoroughly  practical  experiments  which  the  Department  has  con- 
ducted in  the  use  of  steel  in  built-up  gun  construction  in  the  past  four 
years  has  given  its  officers  a  confidence  in  this  method  which  could 
not,  i^erhaps,  have  ])een  acquired  more  thoroughly  in  any  other  way. 
Added  to  this  there  has  been  an  exhaustive  test  of  the  steel  field  guns, 
and  a  perfectly  satisfactory  test  of  an  8-inch  steel  gun  up  to  101 
rounds.  There  is  no  scoring  of  the  bore,  and  since  the  gun  was  hooped 
to  the  muzzle  there  has  been  no  evidence  of  weakness  or  defect  in 
firing  77  rounds. 

The  physical  qualitie^  of  the  steel  forgings  accepted  is  indicated 
by  the  following  table,  which  gives  the  standards  established  from  the 
results  of  tests  of  the  forgings  manufactured,  viz,  by  the  Midvale 
Steel  Company  for  field,  medium  caliber,  and  seacoast  guns,  cjdin- 
drical  hoops  of  assorted  sizes  and  forged  truiniion  hoops;  by  the 
Cambria  Steel  "Works,  for  medium  caliber  gnns  and  cylindrical  hoops 
of  assorted  sizes,  and  by  Sir  Joseph  AMiit worth  &  Co.,  for  tubes  and 
jackets  for  seacoast  guns.  But  the  figures  given  for  cylindrical 
hoops  and  forged  trunnion  hoops  of  American  manufacture  represent 
nearl}'^  the  minimum  results  obtained  from  actual  tests  made. 


Designation  of  piece. 


Tube 

Jacket  

Cylindrical  hoops. 
Trunnion  hoops... 


Length  of 

specimen 

between 

gauge 

marks. 


Incli€><. 
•2.0 
3.0 
4.0 
■  2.0 
3.0 
4.0 
2.0 
3.0 
4.0 
2.0 
3.0 
4.0 


Elastic  limit. 


Load,  per 
square 
inch. 


Pfiundii. 
46, 000 
46, 000 
46, 000 
50, 000 
50,  OUO 
50, 000 
50, 000 
.50, 000 
50, 000 
50, 000 
53, 000 
53,000 


Exten.«ion 
per  inch. 


Thous- 
andths. 
1.533 
1.  .533 
1.533 
1.666 
1.666 
1.666 
1.666 
1.666 
1.666 
1.666 
1.766 
1. 766 


Ultimate 

Modulus  of 

tenacity 

elasticitv. 

per  square 

inch. 

Pounds. 

Pounds.    \ 

30,000,000 

86,000  t 

30, 000, 000 

86,000  1 

30, 000, 000 

86,000  1 

30, 000, 000 

93,000  ! 

30, 000, 000 

93,000 

30, 000, 000 

93,000 

30, 000, 000 

90,,000 

30.030,000 

90,000 

30, 000, 000 

90,000 

30, 000, 000 

90,000  ! 

30, 000, 000 

95, 000 

30, 000, 000 

95,000 

Elonga- 
tion after 
rupture. 


Par  cent. 
22.0 
20.0 
19.0 
19.0 
18.0 
17.0 
18.0 
16.0 
13.0 
18.0 
15.0 
13.0 


The  2.0-inch  specimens  pertain  to  field  calibers,  the  3.0-inch  to 
medium  calibers,  and  the  4.0-iiich  to  seacoast  guns.  The  modulus  of 
elasticit3^  determined  by  tensile  tests,  has  been  found  to  vary  between 
28,000,000  and  32,000,000  pounds,  the  former  for  tubes  and  the  lat- 
ter for  hoops,  but  the  majority  of  the  tests  gave  more  nearly 
30,000,000  pounds.  The  method  of  manufacture  followed  in  the  for- 
gings made  in  this  country  has  been  to  forge  by  hammer,  anneal  at  a 


Ti  GUN   MAKING    IN   THE    UNITED   STATES. 

high  heat  (at  least  as  high  as  that  at  which  pieces  are  subsequently 
treated  for  oil  tempering) ,  then  oil  temper,  and  subsequently  anneal  at 
a  lower  temperature  than  that  used  in  the  oil-tempering  process. 
That  ^Vliitworth's  process  may  become  the  established  one  in  this 
country  is  highly  probable,  but  the  hammered  forgings  now  made  are 
excellent. 

The  hardness  of  this  steel  (somewhat  softer  in  the  tube  metal)  is 
about  21  as  compared  with  copper  at  3.33.  And  in  the  whole  range  of 
physical  properties  the  metal  admirabW  fulfills  the  requisites  of  gun 
construction,  viz:  A  combination  of  strength^  sti/fiiess,  extensiMlity . 
and  superior  hardness  as  compared  with  m\y  other  grade  of  steel  or 
other  metal  adapted  to  the  construction  of  guns  now  made  or  that 
promises  soon  to  be  made  in  suitable  commercial  quantities.  The 
wide  range  of  elastic  extensibility,  combined  with  great  stiffness  (or 
resistance  to  displacement) .  and  a  high  range  of  reserve  ductility,  are 
the  most  valuable  attributes  of  the  metal. 

The  tangential  strength  of  any  properly  constructed  gun.  unless 
there  be  a  decided  difference  in  the  moduli  of  the  metal  composing  the 
wall,  is,  in  general,  measured  by  the  product  of  the  movement,  which 
is  produced  in  the  metal  at  the  surface  of  the  bore,  into  the  modulus 
of  resistance  of  the  metal  in  the  wall  surrounding  the  bore.  To  make 
this  clear,  we  will  discuss  only  the  tangential  extension  limit  of  the 
metal  and  neglect  the  "  set  "  which  might  occur  from  excessive  radial 
compression  of  the  wall  of  tube.  It  is  proper  to  observe  this  latter 
limit  in  deducting  the  shrinkages,  etc.,  for  the  construction  of  a  gun, 
but  from  the  various  resistances  which  go  to  assist  the  tangential 
resistance  of  the  gun  under  fire  we  may  assume  that  its  resistance  to  an 
interior  pressure  is  not  reached  until  the  metal  at  the  surface  of  the 
bore  is  extended  to  its  elastic  limit  of  tangential  or  circumferential 
extension.  And,  further,  it  will  be  understood  that  we  are  now  dis- 
cussing an  all-steel  gun,  whether  built  up  or  solid,  or  any  gini  of  metal 
of  nearly  uniform  modulus  throughout. 

With  such  premises  the  clastic  tangential  strength  of  an}'  properly 
constructed  gun,  based  upon  the  well-established  fact  that  the  most 
dangerous  displacement  of  the  metal,  either  in  the  state  of  rest  or 
action,  takes  place  at  the  surface  of  the  bore,  is  expressed  very  approx- 
imately by  the  following  formula  : 

P  =  C(a+b)E  (D). 

This  equation  is  derived  from  {I)  ApjDendix  B,  bv  placing: 
3(Ri-  Rf,)         _p        _i 
^~    4R?  +  2  \\l     '^^  -E  '  "~  E 

In  which  P  represents  the  pressure  per  square  inch  within  the 
bore  for  the  state  of  action;  C  is  a  constant  whose  value  depends 
only  upon  the  interior  and  exterior  radii  of  the  wall;    a  and  b  rep- 


GUN   MAKING  IN   THE   UNITED   STATES.  75 

resent  the  limits  of  tangential  compression  and  tangential  extension 
in  the  metal  of  the  surface  of  the  bore  for  the  state  of  rest  and  action, 
respectively,  hence  the  sum  (a-fb)  represents  the  whole  range  of 
dilatation  of  the  bore  when  the  gun  is  fired;  and  E  represents  the 
modulus  of  elasticity  of  the  metal  composing  the  tube  and  supposed 
nearly  constant  throughout  the  wall. 

Taking,  for  example,  a  gun  with  thickness  of  wall  equal  to  1^ 
calibers,  Ri=4Ilo  and  the  value  of  the  constant  C  is  0.682,  hence 
equation  (D)  becomes, 

P=0.682  (a+b)  E. 

Xow  to  apply  this  to  various  guns : 

(a)  The  built-up  forged  steel  gun  is  one  in  which  the  principle 
of  initial  tension  is  applied  with  certainty,  and  the  metal,  at  the 
surface  of  the  bore,  is  compressed  with  exactitude  to  the  limit  of 
tangential  compression  in  the  state  of  rest.  Hence  the  range  of 
dilatation  of  the  bore  under  the  action  of  the  powder  gas  pressure,  to 
reach  the  limit  of  tangential  strength,  is  expressed  by  the  sum  (a+b), 
or,  by  2a  if  we  consider  a  equal  to  b  (in  general,  however,  a>b). 

The  value  of  a — the  elastic  extension  or  compression  per  inch — • 
taken  from  the  table  giving  the  physical  qualities  of  the  tube  metal 
is  0.001533,  and  E=30,000,000.  Hence  the  elastic  resistance  of  the 
built-up  forged- steel  gun  is : 

P=0.682  (0.001533)  2X30,000,000=62,744  pounds  per  square  inch. 

The  application  of  this  formula  also  shows  why  it  is  advantageous 
to  the  strength  of  the  gun  to  have  outside  cylinders  with  a  high 
modulus  of  elasticity  relatively  to  the  tube — always  supposing  that 
the  tube  combines  a  high  degree  of  elastic  extensibility  in  connection 
with  its  low  modulus,  for,  in  that  case,  the  value  of  E,  which  in  the 
formula  represents  the  modulus  of  the  tube  metal,  ought  to  be  raised 
to  about  an  average  of  the  modulii  of  the  metal  in  the  different  cyl- 
inders to  reach  an  estimate  of  the  resistance  of  the  gun. 

(5)  In  the  case  of  a  steel-cast  gun  supposed  to  have  been  con- 
structed with  a  properly  regulated  initial  tension.  (See  Appendix  B.) 
If  we  retain  the  modulus  E=30,000,000,  and  take  a=0.001333  and 
b=0.001166,  the  relative  values  corresponding  to  p=40,000  and  ^= 
35,000  pounds  per  square  inch.  The  elastic  tangential  resistance  of 
the  gun  would  be : 

P=0.682  (0.001333+0.001166)  30,000,000=51,150  pounds  per 
square  inch,  which  is  the  same  result  as  will  be  found  deduced  in 
Appendix  B.     (See  Plate  IV.) 

(c)  If  the  steel-cast  gun  be  supposed  without  initial  tension,  that 
is  a  simple,  neutral  wall  of  metal,  a  becomes  equal  to  zero,  and 
6=0.001166  as  before,  then  the  elastial  tangential  resistance  will  be: 

P=0.682X0.001166X30,000,000=23,870  pounds  per  square  inch. 


76 


GUN    MAKING    IN    THE    UNITED   STATES. 


In  this  case,  there  being  no  compression  of  the  bore  to  start  with, 
the  range  of  dilatation  is  on  the  pkis  side  only,  and  the  elastic  tan- 
gential strength  is  curtailed  accordingly.  And  in  general  terms  a 
gun  with  neutral  wall  will  have  only  one-half  the  strength  of  a 


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built-up  wall,  or  one  in  which  there  has  otherwise  been  introduced  a 
proper  degree  of  initial  tension. 

(ri)  A  cast-iron  Rodman  rifle.  For  cast-iron  E= 18,000,000.  Al- 
though it  can  not  be  admitted  that  there  is  any  certainty  in  the 
amount  of  initial  tension  produced  in  a  Rodman  cast-iron  casting, 
we  may  assume  a  most  favorable  case  by  taking  a=0.00122'2  and 


GUX    MAKING   IN    THE    UNITED    STATES.  77 

b=0.000722.  the  relative  values  corresponding  to  p=22,000  and 
^=13,000  pounds  per  square  inch.  Then  the  elastic  tangential  resist' 
ance  of  this  gun  would  be : 

P=0.682   (0.001222+0.000722)   18,000,000=23,870  pounds  per 

square  inch, 
or  the  same  as  the  steel-cast  gun  without  initial  tension. 

These  guns  are  all  taken  to  be  1-i  calibers  in  thickness  of  wall,  and 
a  summary  gives — 

Relative  tangential  resistance  of  homogeneous  guns: 

(a)  Built-up  forged  steel  gun,  62.74'!  pounds  per  square  inch. 

(b)  Steel-cast  gim,  with  proper  initial  tension,  51,150  pounds  per 
square  inch. 

(<?)  Steel-cast  gun,  without  initial  tension,  23,870  pounds  per  square 
inch. 

(d)  Cast-iron  Rodman  rifle,  23,870  pounds  per  square  inch. 

The  12-inch  cast-iron  rifle  recently  tested  at  Sandy  Hook  has  a 
thickness  of  wall  sui-rounding  the  powder  chamber  equal  to  1^  calibers 
nearly,  so  that  the  value  of  the  constant,  C,  remains  equal  to  0.682, 
If  now  Ave  may  be  permitted  to  assiune  that  the  initial  tension  in  this 
gun  is  represented  by  the  value  15,750  pounds  determined  from  the 
breech  initial  tension  ring  by  the  very  crude  and  entirely  unsatis- 
factory method  of  cutting  open  the  ring  as  a  whole.  Then 
J, —     i5T_6_p__ — 0  000875 

'^ T80  00  00  0 — V.UUUOf  o, 

and  retaining,  as  before,  b= 0.000722,  the  elastic  tangential  resistance 
of  this  gun  is  represented  by : 

P=0.682  (0.000875+0.000722)  18,000,000=20,607  pounds  per 

square  inch. 

It  may  be  said  with  perfect  propriety  that  this  gun  has  stood  a 
number  of  rounds  with  greater  pressure  than  this.  So  do  other 
guns  stand  pressures  in  excess  of  the  calculated,  but  it  is  not  safe  to 
subject  them  to  such  pressures,  and  we  may  find  in  this  relative  com- 
parison of  the  strength  of  guns  a  very  good  reason  why  cast-iron 
guns  are  not  reliable.  They  are  at  every  round  with  full  charges 
momentarily  subjected  to  pressures  which  exceed  a  useful  limit  of 
strain,  and  approach  the  limit  of  rupture  of  the  metal.  The  iron  hav- 
ing so  little  extensibility  finally  shows  its  failing  point  in  a  sudden 
and  disastrous  rupture.  There  can  be  no  good  reason  given  why  we 
should  base  the  strength  of  a  cast-iron  gun  upon  the  rupture  limit 
of  the  metal.  The  advocates  of  cast-iron  guns  do  this,  but  it  provides 
no  factor  of  safety. 

We  can  not  apply  the  preceding  rules  to  the  composite  gims  made 
with  a  cast-iron  body  as  the  main  feature,  because  of  the  difference 
in  the  moduli  of  the  metals  composing  the  wall;  the  computation 
of  the  strength  of  these  gims  requires  a  more  extended  application 
of   the   formulas.     Evidently,   however,   in   the   case   of   the  rifled 


78  GUN   MAKING   IN   THE   UNITED   STATES. 

mortars  hooped  with  steel,  the  value  of  the  resistance  P  is  much 
increased  over  what  it  would  be  if  the  piece  were  simply  cast-iron, 
because  of  the  much  higher  modulus  of  elasticity  of  the  metal  of  the 
hoops,  which  are  shrunk  on  to  give  their  full  assistance  to  the  cast- 
iron  in  resisting  the  pressure. 

Again,  if  we  take  the  combined  cast  iron  and  steel  gun,  with  a  steel 
tube  lining,  it  is  not  permissible  to  assume  that  the  bore  of  the  steel 
tube  can  be  made  to  range  through  the  double  limit  of  stretch.  For, 
in  the  first  place,  the  bore  of  tube  is  not  compressed  to  its  limit  in 
the  state  of  rest,  as  in  fact  the  formulas  show  it  to  be  best  to  put  these 
tubes  in  with  a  play,  or  at  most  a  very  slight  shrinkage ;  and,  in  the 
second  place,  the  little  extensibility  of  the  ca!?t-iron  body  in  the  state 
of  action  causes  its  limit  to  be  reached  before  the  bore  of  the  tube 
is  extended  to  its  limit.  Hence,  in  these  guns  the  limit  of  dilatation 
of  the  bore  is  curtailed  on  both  sides,  and  their  elastic  tangential 
resistance  is  considerably  below  that  of  the  built-up  steel  gun. 

We  will  now  revert  to  an  account  of  actual  operations.  The  scope 
of  the  experiments  undertaken  to  develop  knowledge  in  the  construc- 
tion of  built-up  guns  has  already  been  mentioned,  and  the  results 
may  be  summarized.  When  the  making  of  steel  guns  and  steel  forg- 
ings  for  composite  guns  was  authorized  in  this  country  there  was 
little  known  upon  the  subject  of  gun  steel  manufacture,  and  it  was 
difficult  to  obtain  a  correct  loiowledge  of  the  method  of  treatment 
pursued  elsewhere.  Up  to  this  time  the  few  small  gim  forgings  that 
had  been  made  in  this  country  had  been  simply  annealed.  The  scope 
of  existing  information  is  contained  in  a  circular  issued  April  3,  1883, 
by  the  Chief  of  Ordnance  to  steel  makers  in  the  United  States,  and 
afterwards  published  in  his  annual  report  for  1883,  page  6  et  seq. 

The  first  experiment  then  undertaken  by  the  Department  with  the 
able  cooperation  of  Mr.  R.  W,  Davenport,  superintendent  of  the  Mid- 
vale  Steel  Company,  was  to  order  three  experimental  steel  hoops  of 
the  size  required  for  the  guns.  These  hoops  were  furnished  by  the 
Midvale  Steel  Compan}^  as  follows : 

One  rolled  hoop,  annealed,  oil  tempered,  and  finally  annealed 
■    One  rolled  hoop,  annealed  simply. 

One  hammered  hoop,  annealed,  oil  tempered,  and  finally  annealed. 

The  results  of  the  specimen  tests  and  the  shrinkage  tests  ^  were, 
first,  to  establish  the  superiority  of  the  oil-tempered  and  annealed 
metal  on  account  of  its  high  elastic  limit  and  great  extensibility  within 
that  limit ;  and  second,  which  was  not  of  less  importance,  to  establish  a 
striking  similitude  between  the  behavior  of  the  metal  in  the  specimen 
tests  and  that  of  the  hoops  as  a  whole  in  the  shrinkage  tests.  The  first 
of  these  results  was  to  establish  the  manufacture  of  oil-tempered  and 

«  See  Notes  on  the  Construction  of  Ordnance,  No.  25. 


GUX    MAKING   IN    THE    UNITED    STATES. 


79 


annealed  steel  for  future  constructions;  the  second,  which  has  been 

repeatedly     verified     in     experiments 

since  made,  gave  a  basis  for  all  future  |^ 

shrinkage  "\Tork,  since  it  is  upon  the  || 

tests  of  detached  specimens  that  we  if 

must,  in  general,  judge  of  the  physical 

properties  of  the  metal. 

Plate  I,  made  for  the  hammered 
hoop,  is  given  as  an  illustration  of 
these  tests.  The  figures  \Yill  explain 
themselves,  but  we  may  note,  that  tlio 
very  slight  permanent  set  of  the  hoop, 
0.00115  of  an  inch  on  a  diameter  of 
15.75  inches,  following  its  release  from 
shrinkage  in  the  elastic  tests  is  mainly 
due  to  tfie  fact  that  the  hoop  in  this 
test- was  distended  beyond  the  elastic 
limit  of  the  metal  as  shown  by  the 
specimen  tests.  The  diagram  illus- 
trates the  great  elastic  extensibility  of 
steel  as  a  metal  and  its  resilience  even 
when  as  in  the  strength  test  it  was  dis- 
tended for  hours  to  nearl}^  double  the 
elastic  limit  of  the  metal.  The  waves 
of  the  parts  of  the  circumference  of 
the  hoop  corresponding  to  the  lines 
indicate  the  degree  of  uniformity  of 
strength  in  the  different  several  stages 
of  the  tests.  These  lines  represent  the 
development  of  one-half  of  the  interior 
circumference  of  the  hoop. 

The  next  experiments  undertaken 
were  the  construction  of  compound 
cylinders  made  to  be  a  complete  coun- 
terpart of  the  guns  through  the  re- 
enforce  for  three  different  experi- 
mental guns  imder  construction,  as 
already  mentioned.  The  purposes  of 
these  experimental  constructions  were 
fully  realized.  These  purposes  were, 
in  general  terms :  To  obtain  such  data 
as  could  be  made  available  in  the  after  ^ 

construction  of  the  guns ;  to  determine 
the  behavior  of  the  elementary  cylinders  in  combination  under  the 


"  As  here  reproduced  the  scale  of  the  origiual  drawing  has  been  reduced  6J  times. 


80  GUN    MAKING    IN    THE    UNITED   STATES. 

theoretical  shrinkages  previously  deduced  by  a  mathematical  applica- 
tion of  the  formulas  and  thus  test  the  theories  upon  which  the 
formulas  are  based;  to  observe  the  individual  behavior  of  the  ele- 
mentary cylinders;  and,  finally,  to  determine  whether  the  shrinkages 
so  deduced  should  be  applied  in  the  after  construction  of  the  guns  or 
to  what  extent  they  should  be  modified  for  that  construction.  I  will 
here  refer  especially  to  the  results  derived  from  the  construction  of 
the  section  of  the  8-inch  built-up  steel  gim." 

Shrinkage  tests  of  Inunincrcd  mid  oil-tempered  hoop — Midrale  Xo.  9883. 

A^^iat  we  may  call  the  "  hooping  test  "  in  this  case,  which  comprised 
the  successive  shrinkages,  one  upon  another  of  the  4  cylinders  com- 
posing the  section  of  gun  (see  PI.  II)  and  the  successive  dis- 
mantling of  these  cylinders  in  inverse  order,  was  accompanied  by 
numerous  specimen  tests  of  metal  cut  from  the  forgings  both  before 
and  after  their  subjection  to  the  hooping  test.  The  several  cylin- 
ders in  the  section,  viz,  tube,  jacket,  A  hoop,  and  B  hoop,  were 
subjected  to  the  same  treatment  as  required  in  a  gun — that  is,  they 
were  heated  and  shrunk  in  place,  and  when  in  place  were  sub- 
jected to  the  same  amount  of  strain  that  similar  parts  would  have 
in  the  built-up  gun  in  what  is  called  the  "  state  of  rest " — that  is, 
the  normal  state.  The  gun  section  was  left  in  an  assembled  con- 
dition for  several  weeks.  Under  these  circumstances  a  comparison 
of  the  specimen  tests  made  before  and  after  the  hooping  tests 
showed :  The  elastic  j^roperties  of  the  tube  metal  under  compression 
were  decidedly  improved  and  not  materially  affected  in  regard 
to  tensile  qualities.  The  same  was  observed  in  regard  to  the  jacket 
metal  which  had  been  subjected  to  the  heat  of  shrinkage,  but  the 
improvement  under  compression  tests  was  less  marked  than  in 
the  case  of  the  tube.  The  metal  of  both  hoops  showed  a  loss  in 
tensile  qualities  varying  from  4.85  to  9  per  cent,  and  as  a  result 
of  these  tests  it  was  concluded  to  give  the  hoops  a  margin  of  10 
per  cent  on  their  elastic  strength  over  any  anticipated  strains  in 
the  gun. 

In  proving  the  application  of  the  formulas  used  in  deducing 
the  shrinkages  the  radial  changes  of  dimensions  for  all  the  cylin- 
ders throughout  the  section  were  found  to  be  practically  the  same 
as  those  anticipated;  in  fact,  the  results  more  than  fulfilled  the 
best  anticipated,  but  in  respect  to  changes  of  length  in  the  cylin- 
ders the  formulas  did  not  give  accurate  results.  The  formulas 
applied  in  this  case  were  Clavarino's,''  and  it  was  found  that  by  a 
modification  of  these  formulas,  which  consisted  in  neglecting  Clava- 

"  See  Notes  on  the  Construction  of  Ordnance,  No.  .32. 

^  See  Notes  on  the  Construction  of  Ordnance,  Nos.  6  and  7. 


GUN   MAKING   IN    THE   UNITED    STATES. 


81 


rino's  assumption  that  the  interior  and  exterior  normal  pressures 
acting  upon  a  gun  cylinder  do  also  act  upon  the  ends,  as  though 


STAGES  OF  THE  ASSEMBLAGE 


PLATE  II. a 

'         PARTS  PREPARED  FOR 


ASf'^M^LAGE. 


closed.     By  neglecting  this  assumption  a  set  of  formulas^  was  de- 

oAs  here  reproduced  the  scale  of  the  original  drawing  has  been  reduced  4§ 
times. 
*  See  Notes  on  the  Construction  of  Ordnance,  No.  35. 

7733—08 6 


82  GUN    MAKING   IN   THE   UNITED   STATES. 

duced,  with  which  the  results  of  the  hooping  test  gave  an  ahnost 
complete  agreement.  It  must  not  be  inferred  from  this,  however, 
that  Clavarino's  formulas  are  considered  unreliable.  Their  use  will 
probably  enable  the  construction  of  as  well  proportioned  a  gun  as 
any  other;  but  failing  cases  will  be  found  in  their  application  to 
special  features.  A  very  careful  consideration  reached  from  this 
experiment  was  that  the  preliminary  specimen  tests  of  the  metal 
of  the  forgings  determine  suitable  values  for  the  physical  constants 
to  be  used  in  the  computations;  and,  second,  conjointly  with  this, 
the  formulas  applied  can  be  relied  upon  to  indicate  with  accuracy 
the  results  which  will  be  obtained  in  practice.  That  is  to  say,  the 
formulas  are  proved  correct  for  the  various  changes  and  displace- 
ments induced  by  the  pressures  produced  in  shrinking  the  hoops 
together ;  hence  they  may  be  relied  upon  to  indicate  truthfully  what 
will  take  place  in  the  augmentation  of  the  same  pressures  in  the 
state  of  action. 

Plate  II,  which  has  been  carefully  constructed  to  scale,  represents 
the  measured  changes  of  radial  dimensions,  exaggerated  100  times, 
which  took  place  in  each  of  the  cylinders  when  they  were  successively 
shrunk  together  in  this  section.  The  anticipated  compression  of  the 
8-inch  bore  as  deduced  by  the  formulas  was  0.0129  of  an  inch,  and  its 
measured  compression  was  0.0131  of  an  inch;  the  anticipated  exten- 
sion of  the  exterior  diameter  of  the  outer  hoop — 31.5  inches — was 
0.0285  of  an  inch  and  its  actual  extension  was  0.0276  of  an  inch,  an 
absolute  difference  of  less  than  one-thousandth  of  an  inch,  and  entirely 
inappreciable  when  regarded  relatively  as  an  extension  per  inch  of 
hoop  diameter  or  circumference."  The  degree  of  accuracy  obtained 
is  seen  to  be  98  per  cent  of  the  mathematical  result  anticipated.  I 
will  call  particular  attention  to  the  actual  displacements  of  metal  for 
the  different  cylinders  in  order  to  emphasize  the  fact  that  in  a  built-up 
gun  the  shrinkages  are  (and  can  be  readily  made  so)  so  arranged  that 
the  residuum  of  elastic  disfjlacement  in  each  cylinder  is  sufficient  to 
meet  the  greatest  interior  pressure  that  the  gun  is  computed  to  with- 
stand ;  and  in  addition  to  this  the  actual  elastic  resistance  of  the  built-* 
up  forged  steel  gun  is  always  made  much  greater  than  is  necessary  to 
withstand  the  powder  pressure  obtained  in  practice.  Then  it  amounts 
to  this — none  of  the  cylinders  will  be  strained  nearly  to  the  elastic 
limit  by  the  powder  pressure.  Referring  to  Plate  II,  the  maximum 
strains  in  the  several  cylinders  stand  in  relation  to  the  elastic  proper- 
ties of  the  metal  as  follows : 

Bore  of  tube  comjwessed  to  100  per  cent  of  elastic  limit. 

Interior  surface  of  jacket  compressed  to  20  per  cent  of  elastic  limit. 

Interior  surface  of  A  hoop  extended  to  63  per  cent  of  elastic  limit. 

o  See  Notes  on  the  Ck)nstniction  of  Ordnance,  No.  32,  p.  20. 


GUN   MAKING   IN    THE   UNITED    STATES.  83 

Interior  surface  of  B  hoop  extended  to  Co  per  cent  of  elastic  limit. 

Now,  when  the  interior  pressure — which  for  this  state  of  the  sys- 
tem is  7iil — is  introduced,  the  bore  of  the  tube  has  double  its  range  of 
elastic  displacement  to  go  through  before  the  outer  limit  is  reached, 
the  interior  of  jacket  passes  from  a  negative  to  a  very  moderate  posi- 
tive extension  value,  and  the  two  hoops  undergo  a  further  extension 
within  the  margin  of  elastic  strength  left  in  them — their  displacement 
being  relatively  small  in  comparison  with  that  of  the  bore  of  the  tube 
because  of  their  remoteness  from  the  action  of  the  central  force.    A 
confirmation  of  these  experimental  results  is  shown  in  the  drawing 
(Plate  III)  made  to  represent  the  principal  features  of  the  construc- 
tion of  an  8-inch  rifle.'*    Lines  are  drawn  to  represent  the  measured 
compression  of  the  bore  of  tube  due  to  the  shrinkage  of  the  several 
series  or  layers  of  outer  cylinders.''    The  line  of  final  compression  is 
seen  to  be  in  close  proximity  to  that  representing  the  anticipated  com- 
pression, the  slight  excess  of  the  actual  over  and  anticipated  compres- 
sion being  accounted  for  by  the  fact  that  the  tube  actually  used  in  this 
gun  was  a  somewhat  more  yielding  one  than  that  for  which  the  shrink- 
ages were  computed.     If  we  estimate  this  excess,  however,  for  the 
only  part  of  the  bore  designed  to  be  compressed  to  the  full  limit — 
that  is,  for  the  powder  chamber — we  find  the  excess  of  compression  to 
be  but  1  per  cent  more  than  the  anticipated.     With  such  results  ob- 
tained with  a  gun  weighing  13  tons  and  involving  so  many  shrinkage 
surfaces,  is  it  not  safe  for  one  who  has  seen  this  done  to  claim  that 
the  production  of  the  proper  degree  of  tensions  in  a  built-up  gun  is  a 
certain  process  which,  after  the  plans  of  the  gun  are  made,  requires 
only  competent  workmen,  good  machines,  and  requisite  care  in  in- 
spection to  effect  its  accomplishment  ?    Lieutenant  Howard's  report " 
upon  the  construction  of  a  number  of  3.2-inch  field  guns  at  the  West 
Point  Foundry  (where  also  the  8-inch  rifle  was  put  together)  shows 
by  the  coincidence  between  the  anticipated  and  the  actual  tensions 
obtained  in  these  guns,  which  contain  only  one  shrinkage  surface,  that 
the  construction  is  not  only  practicable,  but  its  results  are  sure.     A 
single  shrinkage  surface  makes  the  anticipated  result  more  difficult 
of  accomplishment,  because  if  there  be  two  or  more  such  surfaces  any 
error,  except  what  might  occur  from  actual  carelessness  on  the  part  of 
the  workmen  and  inspector,  due  to  finishing  the  work  for  a  preceding 
surface,  can  be  corrected  in  the  next  shrinkage  applied. 

The  experiments  made  to   determine  the  effect  of  a  high  heat 
upon    oil-tempered    steel    exposed    to   its    action    for   a   short   time 

a  The  vertical  scale  of  relative  compression  is  actually  exaggerated  about  100 
times  only,  instead  of  1,000  times,  as  written  on  the  drawing. 
*  See  Report  of  the  Chief  of  Ordnance,  U.  S.  Army,  1886,  p.  229. 
"  Appendix  Report  of  the  Chief  of  Ordnance,  U.  S.  Army,  1887. 


84  GUN    MAKING    IN    THE    UNITED   STATES. 

showed,  in  one  case,  that  the  physical  properties  of  a  short  section 
of  an  8-inch  tube  were  not  materially  affected  by  pouring  a  quantity 
of  molten  iron  into  a  mold  surrounding  the  steel  piece  and  leaving 
the  iron  in  contact  with  the  outside  of  the  steel  for  three  and  five- 
tenths  minutes.  In  another  case  the  quality  of  the  metal  in  a  short 
cylinder  of  '\Miitworth  gun  steel  was  not  injured  by  the  white  heat  of 
a  furnace  applied  a  sufficient  length  of  time  to  raise  a  part  of  the 
outer  surface  of  the  piece  to  a  dull  red  heat.  In  this  instance  the 
steel  cylinder  was  shrunk  upon  a  core — one  end  and  the  outer 
surface  only  being  exposed  directly  to  the  heat.  The  utility  of 
these  experiments  is  found  in  the  necessity  which  sometimes,  though 
rarely,  arises  to  remove  a  hoop  or  other  cylinder  after  it  has  been 
shrunk  in  place;  indeed  the  whole  gun  can  be  dismantled  in  this 
way  if  necessary.  Pouring  molten  cast-iron  around  the  piece  to  be 
removed  has  been  found  to  be  the  most  practicable  method.  The 
pieces  thus  removed  can  be  used  again,  as  it  is  known  that  the  quality 
of  the  metal  is  not  materially  affected  when  the  operation  is  skillfully 
performed. 

The  experiments "  to  determine  the  amount  of  frictional  resist- 
ance to  the  sliding  of  one  cylinder  over  another  when  shrunk 
together,  in  the  usual  way,  were  made  with  special  reference  to 
determining  what  would  be  the  aggregate  hold  of  the  jacket  shrunk 
upon  the  tube  in  a  gun  due  to  this  source  of  resistance  alone.  That 
is,  to  determine  what  resistance  the  friction  between  the  two  surfaces 
would  offer  to  any  longitudinal  displacement  of  the  tube  in  the 
jacket.  The  tests  were  made  with  special  reference  to  the  plan  of 
pin  coupling  shown  in  the  drawing  (Plate  III).  The  four  pins 
put  in  near  the  muzzle  end  of  the  jacket  would  offer  an  aggregate 
resistance  of  about  1,131,300  pounds  to  shearing,  but  this  being  only 
about  one-third  of  the  total  effort  (3,189,700  pounds)  which  would 
be  exerted  to  separate  the  tube  and  jacket  longitudinally  for  a  pres- 
sure of  45,000  pounds  per  square  inch  on  the  breechblock,  it  was 
necessary  to  depend  upon  the  frictional  resistance  for  material  assist- 
ance, and  hence  it  was  expedient  to  test  the  value  of  this  frictional 
resistance. 

Several  hoops,  three  and  four  inches  in  width,  were  carefully 
prepared  and  shrunk  upon  a  piece  of  gun  tube.  The  pressure 
which  each  exerted  upon  the  tube  was  determined  by  the  usual 
formulas  and  noting  the  effect  of  the  shrinkage.  These  hoops  were 
pushed  off  in  the  testing  machine  at  Watertown  Arsenal.  From 
the  force  required  to  start  and  keep  these  hoops  moving  under  pres- 
sure it  was  found  that  the  frictional  resistance  somewhat  exceeds 
15  per  cent  of  the  normal  pressure  at  the  contact  surface  of  two  steel 

o  Report  of  the  Chief  of  Ordnance,  U.  S.  Army,  1885,  pp.  317  and  321. 


GUN   MAKING   IN   THE   UNITED    STATES.  85 

cylinders  shrunk  together  as  in  gun  construction.  In  the  f^un  shown 
in  the  drawing  (Plate  III)  the  least  pressure  at  any  time  (i.  e.,  in 
the  state  of  rest)  existing  at  the  contact  surface  between  the  tube  and 
jacket  is  7.17  tons  per  square  inch,  as  computed  by  Clavarino's  for- 
mulas. The  area  of  the  surface  of  contact  between  the  two  pieces  is 
8,816  square  inches,  making  the  aggregate  normal  pressure  about 
62,785,000.  Taking,  for  safety,  only  10  per  cent  of  this,  instead  of 
15  per  cent,  we  have  over  6,000,000  pounds  resistance  to  sliding  due 
to  the  friction  alone.  And  as  the  force  tending  to  slide  the  pieces  is 
scarcely  more  than  one-half  of  this,  it  may  be  concluded  that  the 
resistance  to  longitudinal  separation  of  the  parts  of  this  gun  is  amply 
provided  for,  the  pins  being  in  the  nature  of  a  security  against  any 
start  taking  place. 

In  1885,  an  8-inch  forged  steel  trunnion  hooped  was  procured 
from  the  Midvale  Steel  Company.  It  was  the  first  forged  hoop  of 
this  character — for  seacoast  guns — to  be  made  in  this  country,  and  as 
it  was  known  that  the  manufacture  would  present  special  difficulties, 
it  was  determined  to  make  the  first  an  experimental  piece — that  is, 
for  thorough  specimen  and  shrinkage  tests,  to  determine  the  quality 
and  uniformity  of  the  metal  to  be  obtained  in  a  forging  of  that  size 
and  character.  This  forging  was  treated  in  the  usual  way  by  oil 
tempering  and  annealing.  The  results'^  of  the  tests  showed  an  ex- 
cellent, uniform  quality  of  metal  throughout  the  piece,  and  inci- 
dentally demonstrated  a  thoroughly  good  effect  of  the  oil  tempering 
and  annealing  treatment  in  a  thick  and  irregular  forging. 

The  gun  shown  in  the  drawing  (Plate  III)  was  first  tested  in  the 
condition  there  shown— that  is,  without  chase  hooping  to  the  muzzle. 
Since  then,  however,  the  piece  has  been  hooped  quite  to  the  muzzle. 
In  the  first  state,  after  firing  24  rounds,  the  bore  of  the  tube  at  some 
15  inches  from  the  muzzle  was  found  to  have  enlarged  0.006  of  an 
inch.  The  enlargement,  although  small  in  reality,  was  considered 
sufficiently  serious  to  conclude  that  it  would  be  best  to  put  on  the 
chase  hoops,  a  matter  which  had  been  discussed  for  the  original  con- 
struction. This  tube  had  been  received  from  'WTiitworth  &  Co.,  and 
it  was  not  certainly  known  what  method  of  treatment  the  steel  had 
received— that  is,  Avhether  it  had  been  carefully  annealed  after  oil 
tempering.  The  indications  of  the  firing  test  pointed  to  a  zone  of 
compressed  metal  near  the  exterior  surface,  probably  due  to  lack  of 
annealing  after  oil  tempering.  Such  a  condition  would,  as  we  have 
already  discussed,  tend  to  weaken  the  tube  to  support  an  interior 
pressure.  Then,  although  the  gun  steel  procured  from  home  manu- 
facturers was  known  to  be  in  all  cases  carefully  annealed  as  a  final 
operation  in  manufacture,  experiments  Avere  undertaken  to  analyze 
the  condition  of  strains  left  in  a  piece  on  the  one  hand  when  oil 

o  Notes  on  the  Construction  of  Ordnance,  No.  39. 


86  GUN    MAKING    IN   THE    UNITED   STATES. 

tempered  as  a  final  operation,  and  on  the  other  when  annealed  after 
the  oil  tempering.  The  method  of  examination  pursued  <*  was  that 
already  indicated  as  proper  in  examining  into  the  conditions  of 
initial  strains  existing  in  a  Rodman  casting.  The  results,  in  brief, 
were  that  the  pieces  of  tubes  which  Avere  annealed  as  a  jfinal  operation 
were  almost  entirely  free  from  internal  strains,  while  the  one  which 
was  oil  tempered,  and  not  annealed,  exhibited  a  state  of  compression 
over  its  entire  surface  metal,  exterior,  bore,  and.  ends,  while  the 
interior  of  the  mass  was  in  a  state  of  tension.^  It  may  be  well  here 
to  contradict  an  impression  held  b}^  some  that  the  after  annealing  of 
the  gun  steel  removes  all  the  beneficial  efi'ect  of  the  oil  tempering. 
This  opinion  would  not  be  held  by  anyone  made  conversant  with  the 
facts  in  the  case,  as  have  been  demonstrated  by  numerous  tests  made 
with  steel  of  home  manufacture.  This  question  has  been  pretty 
thoroughly  treated  in  the  discusion  before  the  Naval  Institute  in 
January  of  this  year.*^ 

The  fiirst  of  the  new  steel  field  guns — 3.2-inch  caliber — was  made  of 
steel  simply  annealed.  It  has  an  excellent  record  for  endurance,  but 
at  the  end  of  100  rounds  the  bore  showed  an  enlargement  of  0.009  of 
an  inch  at  the  bottom,  thence  gradually  diminishing  to  0.001  of  an 
inch  at  the  muzzle.  All  subsequent  forgings  made  for  these  guns 
have  been  oil  tempered  and  annealed.  In  order  to  test  the  compara- 
tive merits  of  the  two  methods  of  treatment,  100  rounds  were  recently 
fired  from  a  new  gun  at  Sandy  Hook,  with  the  result  that  there  was 
no  ajopreciable  enlargement  of  the  bore,  except  a  slight  enlargement 
near  the  seat  of  the  shot.'^ 

Three  and  tioo-tenths  inch  hreech-loading  -field  guns,  steel. — The 
first  of  these  guns  ^  was  made  at  the  Watertown  Arsenal  in  1884, 
after  designs  prepared  by  the  Ordnance  Board.  The  piece  consists 
of  a  tube  covered  in  one  layer  by  a  jacket,  trunnion  hoop,  sleeve,  and 
key  ring.  All  of  these  parts  are  made  of  forged,  oil  tempered,  and 
annealed  steel,  and  the  outer  layer,  except  the  key  ring,  is  assembled 
by  shrinkage  on  the  tube.  The  jacket  projects  to  the  rear  of  the  base 
of  the  tube,  and  is  threaded  within  the  recess  to  receive  the  base  ring, 
which  holds  within  it  the  slotted-screw  breechblock.     The  trunnion 

"  See  Notes  on  the  Construction  of  Ordnance,  No.  41. 

*  This  last  condition  of  affairs  was  actually  found  to  exist  to  some  extent  in 
the  8-inch  gun  tube.  When  the  outside  of  the  chase  was  turned  to  prepare  for 
hooping  to  the  muzzle  the  bore  of  the  tube  contracteil  as  the  metal  was  turned 
off,  which  plainly  indicated  that  there  existed  a  zone  of  compressed  metal  at  the 
exterior  of  the  tube.  Now  becomes  apparent  the  utility  of  hooping,  for  a  jn-oper 
degree  of  shrinkage  having  been  computed  for  the  muzzle  hooping,  the  applica- 
tion of  the  hoops  put  this  part  of  the  tube  into  the  desired  state  of  initial 
tension,  and  all  the  firing  since  then  has  not  enlarged  he  bore  at  all. 

c  Proceedings  of  the  U.  S.  Naval  Institute — steel  for  heavy  guns  No.  40,  p.  G2. 

<*  Appendix  39,  Report  of  the  Chief  of  Ordnance,  1887. 

e  Report  of  the  Chief  of  Ordnance,  1884,  p.  509. 


GUN   MAKING   IN   THE   UNITED    STATES.  87 

hoop  is  connected  with  the  jacket  in  shrinkage  by  a  lap  joint;  the 
sleeve  abuts  against  the  trunnion  hoop  and  the  key  ring,  which  is 
screwed  on  cold — the  male  thread  being  cut  on  the  tube^fits  close 
against  the  muzzle  end  of  the  sleeve.  The  breech  mechanism  can  be 
adapted  to  use  either  the  Davis  gas  check  or  the  Freyre,  the  latter 
being  a  steel  ring  of  triangular  section  at  the  side,  with  a  thin  front 
rim  or  edge,  which  is  forced  outward  to  seal  the  escape  of  gas  by  a 
conical  forcing  head  on  the  spindle.  Both  descriptions  of  gas  check 
have  been  fired  many  rounds  at  Sandy  Hook,  and  both  have  given 
satisfaction. 

The  piece  weighs  800  pounds,  and  has  a  length  of  bore  equal  to 
26  calibers.  The  first  gun  made  has  been  fired  over  2,400  rounds 
and  is  still  serviceable;  and  several  of  the  25  guns  recently  finished 
have  been  fired  from  100  to  200  rounds,  their  endurance  being  en- 
tirel}^  satisfactory.  The  charge  of  hexagonal  powder  used  with  the 
Freyre  gas  check  is  3.75,  and  with  the  Davis  3.5  pounds;  the  weight 
of  projectile  is  13  pounds.  For  muzzle  velocity  the  3.75  charge  has 
given  1,749  feet  and  the  3.5-pound  charge '  1 .680.  A  range  of  6,479 
yards,  or  3.75  miles,  with  a  mean  deflection  of  95.6  yards  to  the  right, 
is  given  with  20°  elevation.  The  mean  deviation  given  at  1-mile 
range  is  about  3  feet.  Taking  an  average  of  some  900  rounds, 
the  rapidity  of  fire  obtained  has  been  about  70  rounds  per  hour — 
the  maximum  being  46  rounds  in  twenty-six  minutes,  or  at  the 
rate  of  120  rounds  per  hour.  The  type  gun  of  this  caliber  has 
been  tested  and  accepted  by  the  Board  for  Testing  Rifled  Cannon. 
This  board  continued^  the  test  of  the  gun  up  to  an  endurance  of  1,800 
rounds.  The  data  given  above  is  taken  from  the  results  of  trials 
made  by  the  testing  board. 

The  5-inch  breech-loading  siege  rifle  and  7-inch  breech-loading 
rifled  howitzer  were  both  made  at  the  Watertown  Arsenal  under  the 
direction  of  Lieut.  Col.  F.  H.  Parker.  Both  gims  are  after  designs 
made  by  the  Ordnance  Board.  In  general  plan  of  construction  both 
guns,  and  more  especially  the  5-inch  siege  rifle,  are  nearly  a  counter- 
part on  a  larger  scale  of  the  3.2-inch  field  gim.  The  forgings  for 
the  rifle  were  made  by  the  Midvale  Steel  Company.  The  weight  of 
piece  is  3,500  pounds,  and  the  length  of  bore  30  calibers.  It  is  fitted 
with  the  slotted-screw  breech  mechanism  and  Davis  gas  check.  The 
details  of  design  of  7-inch  howitzer  were  worked  up  by  the  late  Lieut. 
William  Medcalfe.  The  piece  is  designed  to  give  6,000  yards  range 
to  a  shell  weighing  105  pounds.  The  length  of  bore  is  12  calibers, 
nearly,  and  weight  of  piece  3,750  pounds.  The  forgings  for  this 
piece  were  made  by  the  Cambria  Steel  Works  and  fully  meet  the 
high  standard  of  quality  prescribed  by  the  Ordnance  Department. 

Eight-inch  'breech-loading  rifle^  steel. — The  manufacture  of  this  gun 
was  completed  at  the  West  Point  Foundry  in  June,  1886.     The  tube, 


88 


GUN    MAKING    IN    THE    UNITED   STATES. 


jacket,  and  trunnion  hoop  forgings  were  procured  from  Sir  Joseph 
Wliitworth  &  Co.,  and  the  remaining  forgings  for  hoops  and  breech 
mechanism  from  the  Midvale  Steel  Company.  The  manufacture  of 
the  gun  was  long  delayed  by  the  nondelivery  of  the  forgings  from 
Whitworth,  which  were  not  finally  received  until  February,  1885. 
The  general  construction  of  the  gun  will  be  sufficiently  explained  by 
the  drawing  (PL  III),  except  the  breech  mechanism,  which  is  of 
the  slotted-screw  system.*^ 

The  elastic  resistance  which  this  gun  will  offer  to  interior  pres- 
sure is  56,000  pounds  per  square  inch.  It  has,  in  firing  with  experi- 
mental powders,  been  several  times  subjected  to  pressures  of  over 
40,000  pounds,  and  two  of  the  records  show  44,500  and  46.300  pounds, 
but  the  usual  pressure  will  not  exceed  36,000  or  37,000  pounds.  In 
any  event,  for  pressures  likely  to  be  obtained  in  service,  the  gun  has 
a  large  margin  of  elastic  resistance.  Up  to  this  time  the  gun  has  been 
fired  101  times,  with  tlie  following  charges:  Two  rounds  with  a 
powder  charge  of  65  pounds;  12  of  85  pounds:  3  of  95  pounds,  and  84 
of  from  100  to  113  pounds  weight.  The  weights  of  projectiles  were : 
In  7  rounds,  182  pounds;  in  4,  235  pounds;  in  1,  250  pounds,  and  in 
89,  from  285  to  302  pounds.  At  the  one  hundred  and  first  round  a 
range  of  10,698  yards,  or  a  little  over  6  miles,  was  obtained  with  a 
charge  of  95  pounds  of  powder  and  289-pound  projectile.  The  muz- 
zle velocity  for  this  charge  was  1,800  f.  s,,  or  about  75  f.  s.  less  than 
woul(4  have  been  obtained  with  a  full  charge  of  suitable  poAvder. 

The  accuracy  of  the  piece  is  remarkable.  Of  five  shots  following 
one  sighting  shot,  fired  at  a  target — range  3,000  yards — ^all  were 
placed  within  a  circle  of  6  feet  diameter. 

The  following  are  some  of  the  results  obtained  in  the  firing  tests  of 
this  gun  in  which  a  number  of  different  experimental  powders  have 
been  used : 


Round 


Powder  charge. 


Kind. 


German 

do 

Dn  Pont,  P.  A 

Du  Pont,  P.  K 

Du  Pont,  P.  N 

German 

do 

Du  Pont,  Q.  M  .... 

Du  Pont,  Q.  U 

Du  Pont,  Q.  Y 

Du  Pont,  Q.  W.  A  . 
Du  Pont,  P.  N.  A.. 


Weight. 


Pounds. 
100 
100 
100 
100 
110 
110 
110 
113 
110 
IM 
105 
113 


Projec- 
tile 
weight. 


Potinds. 
182 
235 
235 
235 
289 
289 
302 
300 
300 
289 
289 
301 


Density 
of  load- 
ing. 


velocity 
per  second. 


0.98 

0.98 

0.98 

1.00 

0.98 

0.936 

0.935 

1.0 


Pressure 

per  square 

inch. 


Pounds. 
29,500 
32, 150 
32, 950 
37, 660 
36,000 
35, 900 
37,000 
37, 640 
40.700 


Muzzle 
energy. 


Foot-tons. 


36, 500 
35,500 


7,066 
7,043 
7,219 
7,133 
7,333 
7,263 
7,073 
7,157 


oA  full  description  of  the  details  attending  the  manufacture  of  this  gun  is 
given  in  a  report  made  by  the  writer.  (See  Report  of  the  Chief  of  Ordnance, 
U.  S.  Army,  1886,  p.  229.) 


GUN   MAKING  IN   THE   UNITED   STATES.  89 

The  results  obtained  with  the  last  samples  of  powder  tried  indicate 
that  the  muzzle  energy  of  the  gun  can  be  placed  at  7,200  foot-tons, 
obtained  with  a  shot  3^  calibers  in  length,  weighing  300  pounds,  and 
without  exceeding  a  pressure  of  37,000  pounds. 

WORK   DONE    BY    THE    NAVY   DEPARTMENT. 

The  brief  outline  that  can  be  given  of  the  work  of  the  Navy  Bureau 
of  Ordnance  will  be  devoted  principally  to  showing  the  remarkable 
progress  that  has  been  made  by  the  Navy  in  the  production  of  built- 
up  forged  steel  guns,  and  that  the  question  whether  this  gun  shall  be 
the  established  type  of  construction  in  this  country  is  no  longer  an 
open  one.  Not  only  is  the  type  of  gun  established,  but  the  home 
manufacture  of  the  forgings  also. 

The  Midvale  Steel  Company,  which  is  amply  able  to  fill  the  orders 
undertaken,  has  supplied,  or  is  now  under  contract  to  supply,  the 
following  comj)lete  sets  of  steel  gun  forgings,  as  given  in  Appendix 
A,  viz,  15  sets  for  3-inch  breech-loading  boat  howitzer,  delivered;  2 
sets  for  5-inch  breech-loading  rifles,  delivered;  52  sets  for  6-inch 
breech-loading  rifles,  of  which  20  sets  have  been  delivered. 

The  recent  contract  made  by  the  Navy  with  the  Bethlehem  Iron 
Company  provides  for  the  delivery  of  about  1,225  tons  of  steel  gun 
forgings  for  6,  8,  10,  and  12  inch  calibers.  Summarizing  the  whole 
number  of  sets  of  forgings,  procured  or  under  contract  for  delivery, 
by  home  manufacturers  for  the  Navy,  there  are  148  sets,  viz,  15 
3-inch,  2  5-inch,  101  G-inch,  4  8-inch,  24  10-inch,  and  2  12-inch :  To 
get  at  the  whole  number  of  guns  made,  or  now  provided  for  in  the 
Navy,  there  must  be  added  to  the  above  list  8  8-inch  and  3  10-inch 
rifles  for  which  the  forgings  were  mainly  procured  from  Charles 
Cammell  &  Co.,  and  Whitworth  in  England.  This  makes  a  total  of 
159  steel  rifles,  of  which  141  are  built-up  forged-steel  guns  of  6-inch 
caliber  and  upward. 

The  first  built-up  forged-steel  gun,  which  was  also  the  first  of  its 
kind  made  in  this  country,  was  an  experimental  6-inch  breech-loading 
rifle.  A  contract  w^as  made  for  this  gun  by  the  Navy  Bureau  of 
Ordnance  witli  the  South  Boston  Iron  Works,  January  5,  1880,  the 
Company  to  furnish  the  steel.  The  tube,  of  annealed  metal,  was 
obtained  from  the  Nashua  Steel  Company,  but  the  jacket  was  sup- 
plied by  Firth,  of  oil-tempered  steel.  The  two  guns  following  were 
also  6-inch,  of  annealed  metal,  the  forgings  for  which  were  procured 
from  the  Midvale  Steel  Company,  under  orders  dated  in  May  and 
June,  1882.  Beginning  with  1883,  the  Midvale  Steel  Company  have 
delivered  or  contracted  for  52  sets  of  annealed  and  oil  tempered  and 
annealed  forgings  for  6-inch  guns.  The  forgings  to  be  delivered 
under  the  contract  made  with  the  Bethlehem  Iron  Company  are  also 


90  GUN    MAKING    IN    THE    UNITED   STATES. 

to  be  annealed,  oil  tempered  and  annealed,  and  it  is  stipulated  that 
the  company  shall  begin  the  delivery  of  the  6-inch  forgings  August 
1,  1888. 

Since  the  commencement  of  the  active  work  allowed  by  appropria- 
tions in  1883  and  subsequent  years,  the  Navy  Bureau  of  Ordnance 
has  procured  the  forgings  for  and  has  completed,  or  nearly  so,  21 
6-inch  rifles,  8  8-inch  rifles,  and  2  10-inch.  Work  on  a  third  10-inch 
rifle,  to  be  34  calibers  in  length  of  bore,  has  been  commenced  with 
forgings  now  at  the  Washington  Navy- Yard. 

Of  these  gims  the  West  Point  Foundry  contracted  for  the  manu- 
facture of  5  6-inch  and  2  8-inch  rifles.  Four  of  the  6-inch  are  com- 
pleted, and  the  three  remaining  guns  are  in  the  final  stage  of  con- 
struction. The  South  Boston  Iron  Company  contracted  for  the 
manufacture  of  6  6-inch  and  2  8-inch  rifles.  Five  of  the  6-inch  are 
completed,  and  the  2  8-inch  are  to  be  completed  in  March,  1888. 

The  Washington  Navy-Yard  has  completed  2  5-inch,  10  6-inch,  4 
8-inch,  and  1  10-inch  rifles,  and  has  another  10-inch  about  three- 
fourths  completed.  Carriages  for  all  the  guns  have  also  been  made 
there,  besides  a  number  of  3-inch  guns  and  projectile  work. 

This  much  has  been  accomplished  since  1883,  notwithstanding  the 
considerable  delays  made  by  waiting  for  the  first  deliveries  of  the 
forgings  and  the  lack  of  machinery  and  plant  for  the  new  and 
superior  quality  of  work  demanded.  At  present  the  Washington 
Nay>^-Yard  has  worked  up  its  plant  to  a  capacity  for  a  yearly  product 
of  25  6-inch  and  10  8-inch  guns  and  carriages,  etc.,  or  a  proportionate 
amount  of  work  on  other  gims.  Plans  are  now  in  process  of  develop- 
ment which  will  make  the  yearly  capacity  of  the  yard  equal  to  com- 
pleting 25  6-inch,  4  8-inch,  6  10-inch,  and  4  12-inch  rifles  or  a 
proportionate  number  of  any  given  calibers. 

The  finished  gims  have  been  subjected  to  the  proof  required  by  law, 
which  constitutes  a  series  of  10  rounds  fired  with  all  possible  dispatch, 
and  a  number  besides  have  been  subjected  to  additional  firings  at  the 
proving  ground  at  Annapolis  and  in  firing  practice  on  shipboard. 

All  are  officially  reported  to  have  withstood  the  firing  tests  per- 
fectly and  to  give  satisfaction  in  service.  One  6-inch  gun  has  been 
fired  about  300  times,  and  in  the  Report  of  the  Secretary  of  the  Navy 
for  1885  it  is  stated  that  6-inch  gun  No.  4  had  been  fired  57  rounds 
and  one  5-inch  gun  26  rounds.  In  the  rapid-firing  tests  the  6-inch 
rifle  was  fired  10  rounds  in  eleven  minutes,  and  the  8-inch  10  rounds 
in  fifteen  minutes,  although  one  of  the  shots  was  accidentally  dropped 
in  this  last  trial  and  occasioned  a  delay. 

In  their  main  features  the  Navy  and  the  Army  steel  guns  are  alike, 
the  most  important  difference  in  construction  being  that  in  the  navy 
guns  the  trunnion  hoops  are  made  of  oil-tempered  and  annealed 
castings  and  are  screwed  on  cold,  while  in  the  Army  gun  designs 


GUN    MAKING   IN    THE   UNITED    STATES. 


91 


these  hoops  are  forged  and  assembled  by  shrinkage.  In  the  matter 
of  charges,  also,  the  practices  differ,  in  that  the  rule  in  the  Navy  is 
to  use  a  charge  of  powder  equal  to  about  one-half  the  weight  of  the 
shot,  while  in  the  Army  the  weight  of  projectile  is  made  proportion- 
ately much  heavier.  The  lighter  projectile  gives  a  high  velocity 
with  a  relatively  fiat  trajectory,  which  is  best  adapted,  as  it  is  claimed, 
to  the  conditions  of  naval  combat.  The  range  given  for  the  experi- 
mental 6-inch  gun  is  3,046  yards  at  3°  10'  elevation  and  7,000  yards 
at  10°  10'  elevation. 

The  weights  of  the  present  type  guns  which  have  30  calibers  length 
of  bore  and  are  hooped  to  the  muzzle,  are:  6-inch,  10,942  pounds; 
8-inch,  28,077  pounds ;  and  10-inch,  57,485  pounds. 

The  charge  determined  for  the  6-inch  is  53  pounds  4  ounces  of 
German  or  48  pounds  2  ounces  of  Du  Font's  brown  prismatic  powder, 
and  100-pound  projectile ;  and  for  the  8-inch  122  pounds  of  German 
or  112  pounds  of  Du  Font's  American  powder,  with  250-pound  pro- 
jectile. It  is  stated  that  the  American  brown  powder  gives  the  same 
muzzle  velocity  as  the  German  with  less  pressure. 

The  velocities  and  pressures  realized  in  the  several  types  of  guns 
reported  in  1886-87  (Report  of  the  Secretary  of  the  Navy)  are: 


Gun. 

Powder  charge. 

Project- 
ile 
weight. 

Muzzle 

velocity, 

per  second. 

Pressure. 

Kind. 

Weight. 

1887 

American . 
do 

Pounds. 
30.5 
54.0 

Pounds. 

60 

100 

Feet. 
2,011 
2, 105 
2, 013 
2,008 

Tons. 
14.2 

1886 

6-inch 

15.6 

1886 

8-inch 

15.5 

1887 

8-inch 

American . 

113.0 

250 

15.5 

I  do  not  know  that  it  will  be  necessary  to  add  to  the  proofs  already 
given  of  the  success  of  the  system  of  built-up  forged  steel  guns  as 
already  achieved  in  this  country.  The  objections  which  have  been 
raised  to  the  adoption  of  the  system  do  not  appear  to  have  any  force 
under  present  circumstances. 

There  is  certainly  no  mechanical  difficulty  in  making  these  guns 
which  can  not  be  overcome  by  the  exercise  of  proper  care  in  manu- 
facture. The  machining  of  the  finished  surfaces  requires  less  care, 
for  instance,  than  is  exercised  in  making  paper  rolls  in  this  country, 
for  which  a  series  of  rolls  several  feet  in  length  must  be  finished  so 
true  that  when  piled  one  on  top  of  the  other  no  ray  of  light  must 
pass  between  them.  A  variation  of  0.003  of  an  inch  is  usually 
allowed  in  turning  the  shrinkage  surfaces  for  a  gun,  which  allows 
any  skilled  workman,  with  even  a  fairly  good  machine,  to  accomplish 
the  desired  result  with  ease,  a  fact  which  any  one  can  ascertain  for 
himself  by  consulting  the  workmen  at  the  West  Foint  Foundry,  or 
any  other  shop  where  nicety  of  workmanship  is  required.     Again, 


92  GUN   MAKING   IN   THE    UNITED   STATES. 

the  shrinkages  required  to  procure  the  maximum  resistance  of  a  gun 
built  up  of  several  layers  are  susceptible  of  interchange;  that  is,  a 
certain  aggregate  effect  is  required  which  may  be  had  by  a  relatively 
heavy  shrinkage  of  the  first  layer  and  a  relatively  light  shrinkage 
for  the  second  layer,  and  so  on,  or  the  reverse.  Measurements  taken 
of  the  bore  after  the  first  layer  is  applied  give  an  accurate  check  upon 
the  result,  and  it  is  then  easy  to  modify  the  shrinkage  for  the  appli- 
cation of  the  next  layer  if  necessary.  The  question  of  making  a 
thoroughly  good  built-up  gim  of  forged  and  oil-tempered  steel  is 
practically  a  question  of  skilled  workmanship  only,  and  all  the 
allowances  which  are  permitted  in  the  accuracy  of  finish  for  the 
work  render  it  not  only  entirely  practicable  but  comparatively  easy 
of  accomplishment. 

The  division  of  the  gun  into  many  parts  has  all  the  advantage  of 
procuring  the  very  best  of  material,  because  of  the  thorough  working 
which  each  part  receives  and  the  facility  for  examination  of  the 
quality  of  the  material  which  is  afforded.  In  the  construction  of 
the  gun  these  different  parts  are  assembled  to  give  a  great  economy 
of  material.  The  jacket  affords  all  the  requisite  longitudinal 
strength  and  also  a  due  share  in  assisting  the  tube  and  hoops  for 
tangential  resistance.  The  hoops  are  needed  for  the  tangential  and 
not  for  longitudinal  strength,  and  the  methods  pursued  in  their 
manufacture  and  application  in  the  gun  structure  essentially  fit  them 
to  afford  the  kind  of  resistance  required  of  them. 

It  has  also  been  objected  that  the  heat  and  strains  due  to  firing 
would  disturb  the  adjustment  of  the  tensions  of  the  several  parts. 
The  best  answer  to  this,  of  course,  is  that  practice  has  proved  the 
contrary.  Again,  Gadaud  mentions  cases  of  hoops  that  were  re- 
moved from  guns  after  long  service — yet  resumed  practically  their 
original  dimensions.  TMien  the  gun  is  fired  the  heat  is  by  no  means 
confined  to  the  tube,  but  extends  through  the  gun.  so  that  the  disten- 
tion due  to  the  heat  is  felt  throughout  the  wall :  but  the  heat  due  to 
firing  does  not  affect  the  strength  of  the  metal,  and  the  distention 
produced  by  the  heat  is  not  an  added  strain,  so  that  an  equilibrium 
is  established  between  the  force  of  the  interior  pressure  and  the 
resistance  of  the  gun  with  strains  upon  the  metal  due  to  this  force 
which  scarcely  exceed  those  occurring  in  the  cold  state.  The  tube 
in  a  built-up  gim  is  subjected  to  the  greatest  strains  in  the  structure, 
and  there  is  always  left  a  large  margin  of  elastic  strength  in  the 
outside  parts.  And  supposing  the  tube  to  be  heated  in  excess,  this 
effect  would  simply  be  equivalent  to  a  case  of  a  gim  assembled  with  a 
greater  shrinkage.  Then,  in  firing,  the  place  of  most  dangerous 
strain  in  the  gun — that  is,  at  the  surface  of  the  bore  of  the  tube — 
would  be  under  a  less  instead  of  a  greater  strain.  The  principal 
objection  has  been  the  idea  that  the  introduction  of  the  manufacture 


GUN    MAKING   IN    THE   UNITED    STATES.  98 

would  require  so  long  a  time  as  to  make  it  expedient  at  least  to  adopt 
some  temporary  system  of  gim  construction  for  immediate  use  in 
case  of  necessity.  But  this  matter  has  now  been  neglected  so  long  in 
regard  to  the  legislation  needed  for  the  making  of  guns  for  the  land 
service  that  at  present  the  manufacturing  facilities  for  making  the 
built-up  guns  are  quite  as  complete  as  those  for  making  any  other 
kind  of  gims;  hence  there  is  no  reason  on  this  score  why  we  should 
not  at  once  proceed  to  manufacture  the  best  gun. 

COMMERCIAL  ADVANTAGES  OF   GUN   AND  ARMOR  FORGING  PLANT. 

The  great  necessity  for  purity  and  strength  of  material  required 
in  the  steel  to  be  produced  for  war  purposes  will,  as  indeed  it  has 
already  done,  give  a  rapid  advancement  in  knowledge  of  how  best 
to  treat  the  metal  in  order  to  get  the  best  results  in  steel  forgings  of 
every  nature  required  for  commercial  purposes. 

The  substantial  interests  that  will  accrue  to  the  conunerce  of  the 
country  by  the  demand  for  guns  and  armor  of  home  production  are 
manifold.  We  have  good  authority  for  the  statement  that  the  United 
States  is  metallurgically  independent  as  to  its  iron  ores,  iron,  and 
steel,  but  it  is  economically  at  a  disadvantage  in  point  of  cost  of 
material  and  labor.  This  disadvantage  works  against  the  growth 
of  large  forging  or  press  plants,  and  also  against  the  production  of 
the  best  grades  of  steel  required  for  many  commercial  purposes.  If 
the  Government  will  demand  guns  and  armor  of  home  or  domestic 
manufacture,  it  will  enable  our  own  steel  makers  to  produce  the 
heavier  forgings  required  for  shipbuilding  and  other  structural 
purposes  to  compete  with  the  foreign  importations  of  such  material 
now  made,  to  increase  the  demand  for  it  in  the  United  States,  and  to 
compete  with  foreigners  for  the  trade  of  neighboring  countries.  In 
other  ways,  also,  the  scientific  investigations  connected  with  the  manu- 
facture of  steel  and  its  appliances  for  war  purposes  will  assist  the 
commercial  interests  of  the  country. 

The  gun  plant  can  be  applied  to  make  the  best  of  steel  for  either 
the  purposes  of  war  or  commerce,  as  has  been  proven  in  the  experience 
of  both  the  establishments  that  have  up  to  this  time  furnished  gun 
forgings  to  the  Government.  The  manager  of  one  of  these  steel 
works  states : 

Undoubtedly  this  experience  has  been  of  very  great  advantage  to  us  in  teach- 
ing what  the  best  molecular  condition  of  the  metal  is,  and  we  take  advantage 
of  the  plant  erected  for  the  ordnance  work  in  our  regular  trade  work  to  give 
our  customers  the  very  best  product  and  also  to  change  or  improve  the  physical 
qualities  of  our  commercial  products  to  meet  the  demands  of  customers.  If  a 
customer  wants  material  in  the  very  best  possible  condition,  we  use  the  proc- 
esses for  ordnance  metal ;  and  in  meeting  the  demand  for  the  very  high  grade 
metal  required  for  ordnance  our  studies  have  caused  constant  improvements 
and  shown  us  how  to  improve  our  regular  product. 


94  GUN   MAKING    IN    THE    UNITED   STATES. 

The  force  of  this  will  be  understood  in  mentioning  an  instance 
where  the  ingots  made  for  a  lot  of  gun  hoops  in  the  first  order  under- 
taken by  a  company  did  not  meet  the  ordnance  requirements  and 
called  forth  the  statement  by  officers  of  the  company  that  it  would 
be  necessary  for  them  to  learn  over  again  "  what  constitutes  sound 
steel ;  "  and  the  next  lot  of  ingots,  produced  by  pursuing  a  ditferent 
method  of  manufacture,  fully  met  the  requirements.  The  method 
of  improving  the  quality  of  car  axles  by  treating  by  the  so-called 
water-tempering  process  at  the  Cambria  Iron  Works  is  very  largely 
due  to  the  care  and  research  made  by  the  capable  officers  of  that  com- 
pany in  studying  the  manufacture  of  ordnance  metal."  If  it  be  true, 
as  has  been  recently  stated,  that  there  is  a  present  tendency  to  return 
to  wrought  iron  for  boiler  plates  and  axles,  the  reason  can  only  lie 
in  a  careless  treatment  of  the  steel  manufactured  for  such  purposes, 
and  it  will  behoove  the  steel  makers  and  mechanical  engineers  to 
learn  generally,  what  many  of  them  do  already  know,  that  it  is  not 
true  even  of  mild  steel  that  "  it  can  be  badly  worked  and  maltreated 
with  impunity,  yet  it  can  be  trusted  under  all  circumstances."  '' 

The  shrinkage  tests  of  steel  hoops  (already  mentioned)  made  in 
connection  with  gun  work,  and  the  formulas  applicable  to  the  shrink- 
ages used  in  guns,  already  established  to  be  so  accurately  consistent 
with  good  practice,  can  be  profitably  studied  in  connection  with  the 
application  of  hooj)s  or  rings  for  strengthening  purposes  generally, 
as  used  in  commerce.  In  general,  if  only  a  single  hoop  or  row  be 
applied  it  will  be  sufficient  to  give  a  shrinkage  somewhat  within  the 
elastic  stretch  of  the  metal  of  the  hoop  to  prevent  an  overstrain.  In 
the  case  of  locomotive  and  car  wheel  tires  it  appears  that  the  follow- 
ing shrinkages  are  in  use  or  recommended:  By  Krupj),  one  one-hun- 
dredth of  an  inch  per  foot  of  interior  tire  diameter;  Pennsylvania 
Railroad  Company,  one-eightieth  of  an  inch  per  foot  of  interior  tire 
diameter;  Midvale  Steel  Compan3%  one  one-hundredth  of  an  inch 
per  foot  of  interior  tire  diameter. 

These  rules  give  (neglecting  the  compression  of  the  wheel  due  to 
the  pressure  of  the  tire)  an  elongation  of  0.833  or  1.04  thousandths 
per  linear  inch  of  interior  tire  diameter  (or  circumference).  They 
observe  the  same  care  with  regard  to  keeping  the  tension  of  the  metal 
within  its  elastic  stretch  as  is  done  in  making  built-up  guns.  And 
the  tires  on  locomotive  and  car  wheels  are  constantly  subjected  to 
the  worst  sort  of  vibratory  action,  yet  they  hold  their  place  for  long 
periods  of  time.  It  may  be  remarked,  however,  that  when  as  in  the 
ordnance  metal  one  has  a  steel  possessing  (for  hoops)  from  1.75  to 

a  Steel  Car  Axles,  by  John  Coffin.  Phila.  Amer.  Soc.  of  Mech.  Eng.,  Nov., 
1887. 

*  Edward  Bates  Dorsey,  C.  E.  Paper  read  before  the  U.  S.  Naval  Institute, 
Jan.  5,  1887. 


GUN    MAKING   IN    THE   UNITED    STATES.  9§ 

2.0  thousandths  elastic  stretch,  the  shrinkage  of  a  strengthening  ring 
might  well  be  made  as  great  as  1.5  thousandths  per  linear  inch  of 
interior  diameter  or  between  one-fiftieth  and  one-sixtieth  of  an  inch 
per  foot,  and  this  would  presuppose  a  highly  resistant  interior  body, 
such,  for  instance,  as  the  case  of  a  ring  shrunk  upon  a  solid  shaft. 
With  a  hollow  interior  body  where  an  overcompression  from  the  ring 
might  be  feared,  it  would  of  course  be  necessary  to  use  a  proper 
thickness  of  ring.  Economy  of  metal  for  the  strength  required 
would  always  be  obtained  by  using  the  highly  elastic  and  strong 
ordnance  metal  with  the  greater  degree  of  shrinkage  to  which  it  is 
adapted. 

To  cite  an  actual  case  of  a  hammer  used  for  forging :  The  hammer 
head  of  steel  is  held  in  place  by  being  shrunk  on  the  end  of  the  bar. 
It  had  been  assembled  with  a  shrinkage  of  five  sixty-fourths  of  an 
inch  on  19^  inches  diameter;  with  this  shrinkage  the  socket  of  the 
head  broke  or  cracked  under  usage.  The  shrinkage  was  then  reduced 
to  three  sixty-fourths  of  an  inch,  but  the  results  were  still  unsatis- 
factory and  the  head  was  found  to  stretch  and  work  loose.  The 
attention  of  the  management  then  having  been  drawn  to  the  shrink- 
age tests  of  the  gun  hoops,  the  results  were  applied  to  the  case  of  the 
hammer  head  and  a  shrinkage  of  three  one  hundred  and  twenty- 
eighths  of  an  inch  determined  upon.  This  value  gives  a  stretch  not 
to  exceed  1.2  thousandths  per  linear  inch  of  socket  diameter.  After 
this,  when  the  bar  broke  at  one  time  and  was  removed  the  socket  of 
the  head  resumed  its  original  diameter.  Since  the  last  application 
with  the  proper  shrinkage  (three  one  hundred  and  twenty-eighths) 
the  hammer  has  been  in  constant  use  for  about  eighteen  months  and 
no  trouble  has  been  experienced  and  no  movement  of  the  head  has 
taken  place. 

Mr.  Morgan,  of  the  Cambria  Works,  states  that  pieces  of  gun 
steel  rejected  in  the  forgings  made  for  that  purpose  can  be  worked 
down  to  small  sizes  for  commercial  uses,  and  from  the  excellence  of 
the  stock  and  its  thorough  working  will  bring  the  highest  market 
prices."  Certainly  also  there  would  not  be  a  total  waste  of  any 
rejected  piece  of  forging,  since  it  could  always  be  handled  by  the 
plant  at  hand,  and,  as  a  last  resort,  heated  and  cut  up  under  the 
hammer  for  remelting.  Supposing  that  steel-cast  guns  were  in 
vogue,  any  rejected  casting  of  large  size  would  be  a  total  waste,  as 
there  would  be,  presumably,  no  hammer  plant  at  hand  of  sufficient 
size  to  handle  or  break  it  up.  The  large  castings  for  steel-cast  guns 
might  be  cut  up  in  lathes  to  dimensions  sufficient  to  break  up  under 
light  hammers,  but  the  cost  of  this  operation  would  probably  preclude 

«  Our  Coast  Defense,  its  Cost  and  its  Mechanical  Problems,  by  Jos.  Morgan, 
jr.,  Amer.  Soc.  of  Mech.  Eng.,  fifteenth  meeting.     Washington,  1887. 


96  GUN    MAKING   IN   THE   UNITED  STATES. 

its  adoption.  Finally,  on  this  subject,  the  establishment  of  several 
gun  and  armor  forging  plants  will  place  the  country  in  a  position  to 
be  independent  of  foreign  products  for  its  supply  of  such  war  ma- 
terial— a  position  demanded  in  time  of  peace  and  absolutely  essential 
in  time  of  war. 

THE   PNEUMATIC    DYNAMITE    TORPEDO    GUN.^ 

The  pneumatic  dynamite  gun  which  has  recently  been  brought  for- 
ward promises  to  serve  an  important  place  as  an  adjunct  to  other 
means  of  torpedo  defense  and  long-range  armor  piercing  guns  in 
any  system  of  harbor  defense  that  may  be  adopted.  The  possibili- 
ties of  its  use  in  naval  warfare,  especially  on  board  of  harbor  defense 
vessels,  in  which,  probably,  its  greatest  scope  of  usefulness  will  be 
found,  need  not  be  more  than  mentioned  here.  But  if  the  present 
promise  of  the  gun  is  borne  out  in  extended  application  to  suit  the 
varied  conditions  of  service,  it  will  become  a  necessity  for  the  land 
defense,  and  should  be  used  as  a  gun  of  position  forming  part  of  the 
shore  armament.  The  trials  which  have  been  made  with  an  8-inch 
gun  of  this  caliber,  at  Fort  Lafayette,  have  demonstrated  the  fact 
that  charges  of  55  pounds  of  explosive  gelatin  and  dynamite  can  be 
thrown  to  a  distance  of  about  1,800  yards,  with  a  striking  degree  of 
accuracy,  the  total  weight  of  projectile  in  this  case  being  136:^  pounds. 
The  same  gun,  according  to  the  report  of  the  naval  board  which  wit- 
nessed trials  with  the  gun  in  March,  1887,  gave  a  range  of  3,8G8 
yards  or  2.2  miles  with  a  projectile  weighing  139^  pounds. 

The  great  advantage  of  this  gim  appears  to  lie  in  its  ability  to 
throw  large  charges  of  high  explosives  with  entire  safety,  using  com- 
pressed air  as  a  propulsive  force,  which  may  be  exploded  with  destruc- 
tive effect  upon  the  deck  of  a  hostile  ship,  or  with  even  greater  effect 
by  means  of  the  salt-water  fuze  used  with  the  projectile  beneath  the 
water  under  or  near  the  ship. 

The  pneumatic  gun  can  not  be  considered  a  simple  contrivance, 
nor  will  the  establishment  of  a  number  of  them  in  our  seacoast  forts, 
if  such  a  state  of  affairs  is  reached,  be  an  inexpensive  matter.  Its 
success  so  far,  however,  is  certainly  encouraging  and  has  warranted 
the  recommendation  of  the  Chief  of  Ordnance  to  purchase  a  gun  of 
the  class  for  trial. 

The  range  of  modern  heavy  guns  from  shipboard  is  from  7  to  8 
miles,  and  it  is  an  absolute  necessity  for  any  properly  arranged  sys- 
tem of  seacoast  or  harbor  defense  that  such  guns  should  be  met  by  a 
number  of  equally  effective  guns  from  shore. 

6  See  Journal  of  the  Military  Service  Institution,  June,  1887,  vol.  8,  No.  30,  p. 
169. 


GUN    MAKING   IN    THE   UNITED    STATES. 


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98  GUN   MAKING   IN   THE   UNITED   STATES. 

Appendix  B. 

INITIAL   TENSION    IN    GUN    CONSTEUCTION. 
[DISCUSSED   WITH    EBFBRBNCB   ESPBCIALLY    TO    ITS   APPLICATION    IN    STEEL-CAST    GDNS.] 

The  object  here  will  be  to  show  what  state  of  initial  tension  should  be  intro- 
duced in  a  hollow  steel  casting  to  put  it  in  condition  to  resist  the  greatest  inte- 
rior pressure  compatible  with  the  dimensions  of  the  cylinder  and  the  quality  of 
its  metal.  It  is  immaterial  to  this  discussion  whether  the  tension  be  introduced 
in  cooling  as  with  a  hollow  casting,  or  whether  the  casting  be  made  solid,  then 
bored  and  put  in  the  proper  state  of  tension  by  subsequent  operations — provided 
only  the  metal  is  sound  and  good  throughout. 

To  make  the  resistance  to  interior  pressure  a  maximum,  the  state  of  initial 
tension  should  be  such  that  when  the  pressure  acts  from  within,  the  thicliiiess 
of  metal  though  the  wall  of  the  piece  should  be,  as  nearly  as  practicable,  uni- 
formly strained  to  the  elastic  limit  of  the  metal. a  The  aggregate  resistance  of 
all  the  cylindrical  laminte  would  then  evidently  be  a  maximum,  and  it  is  this 
aggregate  resistance  which  holds  the  interior  pressure  in  equilibrium.  In  the 
initial  state  of  a  gun  or  cylinder  constructed  to  fulfill  this  object,  the  interior 
portion  of  the  wall  rests  in  a  state  of  tangential  compression  which  is  greatest 
at  the  surface  of  the  bore,  and  the  exterior  portion  in  a  state  of  tangential 
extension  which  is  greatest  at  the  outside  surface.  The  strains  of  compression 
and  extension  are  in  equilibrium — the  aggregates  of  the  two  being  equal  quanti- 
ties. There  will  be  a  neutral  lamina  in  the  wall  where  the  tangential  strain  is 
virtually  zero,  and  from  this  locality  the  compressions  should  increase  progres- 
sively toward  the  bore  and  the  extensions,  lilvcwise,  toward  the  outer  surface. 
If  the  initial  tension  be  properly  regulated,  the  maximum  place  of  strain  will  be 
at  the  surface  of  the  bore,  hence  if  the  tangential  compression  there  be  limited 
to  the  elastic  limit  of  the  metal  under  compression  the  strain  will  nowhere 
exceed  the  elastic  limit  of  the  metal. 

To  illustrate  the  problem,  take  the  case  of  a  gun  of  8  inches  calilier,  having  a 
thickness  of  wall  in  front  of  the  powder  chamber  equal  to  li  times  the  caliber 
of  the  gun. 
Let— 

P       =  Interior  pressure  per  square  inch. 

p        =  Force  corresponding  to  compression  of  metal. 

6        =  Force  corresponding  to  extension  of  metal. 

p      \      The  radial  pressure  and  tangential  tension  for  tlie  state  of  action, 

t       /  at  any  point  at  the  circumference  of  a  circle  of  radius  r. 

P,      >=  Similar  quantities  for  the  state  of  rest. 

Rq      =  Radius  of  bore,  and  Rj  =  exterior  radius  of  cylinder. 

E       =  Modulus  of  elasticity  of  metal. 

p  and  G  may  not  exceed  the  limit  of  elasticity  of  the  metal  under  free  tests. 

Considering  the  section  in  front  of  the  powder  chamber,  we  have  Ro=4  and 
R  =  16  inches,  and,  as  representing  the  forces  which  would  cause  the  limit  of 
elastic  displacement  of  the  metal  to  be  reached  under  tests  of  free  specimens,  the 
following  values  are  considered  fair,  viz : 

p  =  40,000,  e  =  35,000  pounds  per  square  inch. 

The  following  equation  gives  the  value  of  the  interior  pressure  or  the  elastic 
resistance  upon  the  supposition  that  the  surface  of  the  bore  undergoes  a  range  of 

a  It  will  be  .shown  hereafter  that  for  a  given  quality  of  metal  a  condition  of  uniform 
strain  throughout  the  wall  eqtial  to  the  elastic  limit  of  the  metal  can  l)e  attained  for 

a  certain  thickness  of  wall  only,  that  is  for  a  given  value  of  the  ratio  t>^  in  which  R, 

XVq 

represents  the  exterior  and  Rq  the  interior  radius  of  the  piece. 


GUN   MAKING   IN    THE   UNITED    STATES.  99 

dilatation,  from  the  state  of  tangential  compression  represented  by  p  to  the  state 
of  tangential  extension  represented  by  6,  viz : 

3  (Rf-Rf) 

P  = (p  +  e) (l)a 

4Rf  +  2Rf 

Tlie  relation  between  P  and  6,  such  that  for  a  given  value  of  P,  6  or  the  tangential 

Ar 
extension  (otherwise  expressed  by       E  =  6)  shall  have  a  uniform  value  throughout 

the  thickness  of  the  wall,  is  expressed  by  the  following  equation,  viz: 

P 

=aP  .. (2)6 


(t)' 


°'  Derived  from  equation  A,  p.  27,  Note  35,  making  1  =  0.  Strictly  speaking, 
the  maximum  resistance  in  any  case  should  be  limited  to  preserve  the  metal 
from  excessive  displacement,  whether  by  tangential  extension  or  radial  com- 
pression (in  state  of  action),  but  the  initial  state  which  would  insure  a  maxi- 
mum resistance  is  the  same  in  either  case,  and  for  the  present  we  will  neglect 
the  limit  of  radial  compression  which  would  give  a  less  value  for  P  and  would 
be  derived  from  equation  B,  p.  27,  Note  35. 

6  Deduced  by  Lieut.  William  Crozier,  Ordnance  Department,  U.  S.  Army,  as 
follows : 

From  the  first  of  the  expressions,  p.  3,  Note  35,  with  q  =  o,  we  have : 


whence 


Q=t+| (a) 

The  interior  pressure  estimated  for  any  radius  r  intermediate  between  Ro  and 
Ri  will  be  in  equilibrium  with  the  sum  of  all  the  tensions  acting  in  the  thickness 
Ri  —  r,  and  we  have  : 


Differentiating  and  reducing, 

pdr+  rdp  =  -f  6  -  |J  dr, 


rdp  =  (-0+I-P)  dr  =  -  (Q  +  f  P)  dr 
dp  dr 


e  +  fp        r 

Intergrating  between  the  limits  r  and  Ri, 

fi(e  +  !p)=-ir  +  ic 

For  r  =  Ri,  p=o,  then: 

f  U^  +  f  P)  -f  16=lRi-lr 


.(b) 


(e  +  fp)^=^^^ 

r 

P  =  fe[(^)*-^] (c) 


100  GUN    MAKING    IN    THE    UNITED   STATES. 

Substituting  the  value  of  6  from  (2)  in  (1),  combining  the  two  equations,  we 
find: 

3  (Rf-Rf )  P 
P  = (3) 

(4Rf +  2R§)-3(Rf-Rf)a 

It  is  evident  from  this  equation  that  the  greatest  possible  value  for  p  will  give 
a  maximum  value  for  P.     Substituting  known  values  (p  =  40,000,  etc.),  we  find: 

P  =  38,910  pounds  per  square  inch, 

and  this  value  in   (2)   gives:  tf  =  17,067  pounds  per  square  inch,  from  which 

—  =  0.00058852  is  the  extension  per  linear  inch,  uniform  through  the  thickness 
r 
of  the  wall  for  P  =  38,910.     Since  P  is  a  maximum,  this  value  of  0  is  also  a 

maximum  under  the  condition  for  both,  that  6  shall  be  uniform.     This  condition 

is  introduced  principally  with  reference  to  a  discussion  of  the  state  of  rest  of  the 

system,  to  give  a  datum  line  from  which  to  lay  ofE  the  ordinates  of  the  curve  of 

initial  tension,  as  shown  hereafter.     The  maximum  value  of  P,  if  we  admit  the 

full  limit  of  tangential  extension,  is,  properly  speaking,  51,150  pounds,  which  is 

the  value  corresponding  to  ^  =  35,000  pounds  and  is  derived  from  equation  (1). 

The  particular  state  where  d  is  uniform  and  equal  to  17,067  pounds  and  P  is 

equal  to  38,910  pounds  marks  an  intermediate  stage,  which,  however,  is  entirely 

compatible  with  the  greatest  value  for  P,  viz,  51,150  pounds.     We  ought  not, 

however,  to  consider  this  latter  an  entirely  safe  pressure  for  the  gun,  since,  as 

might  readily  be  shown,  this  pressure  would  cause  the  laminae  near  the  surface 

of  the  bore  to  be  overcompressed  in  a  radial  direction.    The  limit  of  tangential 

compression  of  bore,  system  at  rest,  being  represented,  as  before,  by  p  =  40,000, 

the  value  of  P  which  would  cause  the  limit  of  radial  compression  to  be  reached 

in  the  state  of  action  is  given  by  the  following : 

2  (Rf-Rf) 

P  = p  =  38,710  pounds (4)a 

2  R^ — ^Rj 

This  is  the  safe  theoretical  value  for  the  pressure  to  which  the  gun  might  be 
subjected;  it  corresponds  nearly  with  the  value  (38,910)  which  we  have  found 
would  produce  the  uniform  extension,  6  =  17,067  pounds,  throughout  the  wall, 
and  it  would  therefore  be  a  good  value  to  adopt  in  practice.  The  thickness  here 
used  (1^  calibers)  would  probably  be  a  good  value  to  adopt  for  a  steel-cast  gun 
made  with  initial  tension. 

CUKVE   or   INITIAL  TENSION. 

We  now  pass  to  a  consideration  of  the  system  at  rest — that  is,  the  state  in 
which  the  interior  pressure  is  supposed  removed.  The  curve  of  initial  tension 
which  is  shown  in  fig.  1  (PI.  IV)   is  laid  off  for  values  of  p  below  the  middle 

line  and  for  values  of  6  above  that  line.    These  values  are  equivalent  to  j^^  e 

r 

and  if  we  divide  through  by  E  for  the  several  points  of  the  curve  we  would 

obtain  values  representing  the  displacements  of  the  metal  at  such  points,  and  the 

curve  does,  properly  speaking,  represent  the  displacements   (corresponding  to 

p  or  d)  caused  by  the  joint  action  of  the  radial  pressure   (p')   and  tangential 

tension  (f)  acting  at  the  circumference  described  by  radius  r. 

a  From  equation  B,  p.  27,  Note  35,  making  l=o. 


GUN    MAKING   IN    THE   UNITED   STATES.  101 

Substituting  Ro  for  r,  p  becomes  P,  then 

p=5'[(l)'-'] <*' 

\Ahence 


(1)^ 


(2) 


-1 


In  any  state  which  we  may  consider  (within  proper  limits  of  elasticity)  the 
force  tf  at  a  radius  r,  which  is  created  by  the  action  of  the  interior  pressure  P, 
is  expressed  by  the  following :  o, 

g_/^       2  Rg               4  Rf  Rg            J^\  . 

'v3(Rf-Rg)  +  3(Rf-R§)X    ^2  J^ w; 

If  we  substitute  — P  for  P,  the  resulting  value  of  d  will  give  the  change  that 
occurs  in  d  for  the  given  variation  in  the  pressure.  We  take  that  particular 
state  of  the  system  in  which  e= 17.067  pounds  is  uniform  throughout  the  wall 
and  for  which  P=38,910.  Then  from  the  horizontal  line  which  represented  this 
value  of  0  in  fig.  1  we  may  lay  off  the  several  values  found  for  changes  in  0 
corresponding  to  given  values  of  r.  To  refer  the  points  of  the  resulting  curve 
to  the  zero  line  of  the  figure  and  substituting  P= — P= — 38,910,  the  above 
equation  is  written, 

^(^)  =  -(3-(W^R!)+3l|t||)  7^)  38910+17067 (6) 

The  values  of  6  for  r=4".0,  4".75,  6".0,  8".0,  10".0,  12".0,  14".0  and  16".0  are 
laid  off  in  the  figure  to  locate  the  curve,  and  are  given  in  Table  A,  which  follows. 

It  will  be  observed  that  at  the  point  where  the  curve  crosses  the  middle  line 
the  displacement  is  zero.  The  particular  value  of  r  for  this  neutral  point  is 
expressed  as  follows  :  & 


Ri-Rs(|)» 


.(7) 


This  value  depends  only  upon  the  fixed  dimensions  of  the  cylinder ;  it  is 
independent  of  the  magnitude  of  the  initial  tension,  hence,  for  a  cylinder  of 
given  dimensions,  every  curve  of  initial  tension  (within  proper  limits)  which 
might  occur  should  pass  through  the  same  point.  If  the  neutral  point  were 
found  much  removed  from  the  place  indicated,  it  would  afford  evidence  of  fault 
and  probably  hurtful  strains.  At  the  same  time,  also,  there  might  be  dangerous 
local  strains,  counterbalancing  in  effect,  even  though  the  neutral  point  were 
found  at  its  true  position.  A  good  idea  of  the  adequacy  of  the  initial  tension 
would  be  had  by  observing  the  expansion  of  a  thin  iron  ring  of  metal  detached 
next  the  surface  of  the  bore,  but  in  order  to  make  a  proper  examination  an 
entire  section  of  the  casting  should  be  divided  into  thin  rings,  as  exemplified  in 

a  From  equation  (6)  p.  4,  Note  35,  making  as  should  be  in  the  case  P'=0. 
6  For  this  point,  0  has  the  value  given  by  the  equation  (2)  or 

p 


6=\ 


m 


Substituting  this  value  for  9  in  the  first  member  of  equation    (5),  dividing 
through  by  P  and  reducing,  we  obtain  the  equation. 


102  GUN    MAKING   IN    THE    UNITED   STATES. 

Notes  on  the  Construction  of  Ordnance,  No.  38.     It  would,  of  course,  be  neces- 
sary to  make  this  examination,  at  least  in  part,  in  order  to  locate  the  neutral 
point 
The  remaining  curves  shown  on  figs.  1  and  2  are  deduced  as  follows : 
First,  take  the  state  of  action  corresponding  to  P=38,910  and  0=11,067  con- 
stant throughout  the  wall.    The  two  forces  whose  combined  action  produces  the 

curve  of  uniform  extension  (  —  E=^)  corresponding  to  6  are  the  radial  pres- 

r 
sure  and  tangential  tension  p  and  t,  and  the  equations  of  their  curves  are  given 
by  formulas  (c)  and  (a),  viz: 

p=3/^9[(^y-i] (c) 

t=e-i  p (a) 

or,  by  combining  these,  the  value  of  t  expressed  directly  in  terms  of  0  and 
dimensions  of  the  cylinder  becomes : 


'=H-C(tO'-]} '^' 


Again,  considering  this  particular  state  of  action,  we  may  pass  to  the  state  of 
rest  by  assuming  the  interior  pressure  removed,  which  is  indicated  by  making 
P= — P,  as  was  done  to  determine  the  curve  of  initial  tension.  The  variation  in 
the  pressure  at  any  point  for  radius  r,  corresponding  to  a  variation  in  P,  is 
expressed  by  the  formula :  o 

Pi=rTrRT=R|)^*''"       ^^ 

Po  is  placed  equal  to  —  P,  and  this  value  being  assigned  evidently  indicates 
the  removal  of  the  interior  pressure,  hence  pi  gives  the  variation  of  pressure  in 
passing  from  the  state  of  action  to  the  state  of  rest  The  pressure  existing  in 
the  state  of  rest  is  then  the  algebraic  sum  of  the  pressure  previously  existing  for 
the  radius  r  in  the  state  of  action  and  the  variation  of  that  pressure,  hence : 

p'=P+Pi (9) 

The  values  of  p  to  be  introduced  here  are  to  be  found  from  equation  (c). 
The  deduced  values  of  p'  give  the  curve  of  pressure  for  the  state  of  rest  shown 
in  Fig.  1. 

For  the  curve  of  tension  in  that  state  we  have,  similar  to  (a) 

t'=0  ip)-i  p' (10) 

In  which  the  values  of  0  are  to  be  found  from  equation  (6). 

As  before  remarked,  the  curve  of  initial  tension  represents  a  curve  of  displace- 
ments due  to  the  aggregate  effect  of  the  forces  p'  and  t'. 

Returning  to  the  state  of  action  shown  in  Fig.  2  and  considering  the  pressure 
P  increased  from  38,910  to  51,150  pounds,  we  have  a  positive  variation  of 
51,150—38,910=12,240  pounds  in  the  value  of  P.  The  variations  in  the  value 
of  0  corresponding  to  this  variation  will  be  laid  off  in  a  positive  direction  from 
the  line  of  uniform  extension  5=17,067,  but  in  order  to  refer  to  the  middle  line 

<»The  simplest  form  of  equation  (33),  p.  26,  Note  35,  when  Eo=Ei  (2  cylin- 
ders). 


GUN   MAKING   IN    THE   UNITED    STATES.  108 

of  the  figure  as  the  datum  line  we  use  the  form  of  equation  (6).     The  curve  of 
extensions  for  P=51,150  is  then  determined  by 


-^-f      2Ro  4Rf  Rg  J_\ 

V3(R?-Rg)+3(Rf-Ri)  ^    r,J 


P  +  17067 (ii; 


In  which  P  is  equal  to  12,240  pounds." 

The  ordinates  for  the  several  curves  as  determined  by  the  equations  given  for 
progressive  values  of  r,  together  with  the  displacement  per  linear  inch  corre- 
sponding to  p  and  e,  are  given  in  the  following  table.  The  modulus  of  elasticity 
E  is  assumed  to  be  29,000,000  pounds.     (See  Table  A.) 

The  indicated  strains   (values  of   zLl  )    under  "Initial  tension  curve"  are 

r 
expressed  in  terms  of  the  displacements  per  linear  inch;    they  are  negative  or 
compressions  from  the  bore  to  the  neutral  point  and  positive  or  extensions  thence 
to  the  exterior. 

The  section  to  be  examined  should  be  preferably  first  turned  and  bored  to  the 
dimensions  of  the  finished  piece  and  then  cut  into  concentric  rings,  say  1  inch 
in  thickness.  Before  cutting,  a  light  circle  should  be  scored  on  the  middle  of 
the  face  of  each  ring  and  several  diameters  carefully  measured.  These  measure- 
ments repeated  after  the  separation  of  the  ring  will  give  a  measure  of  the  force, 
whether  positive  or  negative,  by  which  the  ring  was  held  in  restraint.  The 
mean  expansion  or  contraction  divided  by  the  diameter  of  the  measured  circle 

will  give  the  value  corresponding  to   — ^^  and  this  quotient  multiplied  by  the 

modulus  of  elasticity  of  the  metal  will  give  the  value  p  or  0,  corresponding 
respectively  to  the  measured  expansion  or  contraction.  If  the  diameter  be 
called  D  and  the  measured  change  of  diameter  d,  the  expansions  are  as 
follows  :^ 

"The  curve  designated  approximate  pressure  curve  for  P=51,150  is  so  far 
fixed  only  by  the  ordinates  at  the  extremities.  The  interior  one  is  given  and  the 
exterior  pressure  is  only  the  atmospheric  pressure  which  is  counted  nil.  The 
form  of  (8)  and  (9)  would  be  applied  to  determine  intermediate  points  of  the 
curve. 

*  The  method  of  conducting  this  test  is  explained  in  Notes  on  the  Construction 
of  Ordnance,  No.  38. 


104 


GUN    MAKING   IN    THE    UNITED   STATES. 


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GUN   MAKING   IN    THE   UNITED    STATES.  105 

--E=p  and  ^v  -1^=6 (n)a 

The  powder  chamber  would  be  made,  we  will  say,  with  a  diameter  of  9.5 
inches  or  Ro=4.75.  In  order  to  avoid  the  disturbance  of  the  initial  state  which 
would  result  from  enlarging  to  this  size  a  bore  made  somewhat  less  than  8 
inches  in  the  rough,  it  would  appear  advisable  to  make  the  chamber  nearly  full 
size  in  the  rough  form  before  introducing  the  initial  tension  by  either  method 
that  might  be  used.  However  this  may  be,  the  uncertainties  of  the  manufacture 
are  such  that  it  is  unimportant  to  consider  here  the  disturbance  which  might 
arise  in  reaming  out  the  chamber,  and  we  will  assume  the  interior  surface  there 
to  be  also  compressed  tangentially  to  the  limit  p=40,000. 

Applying  equation  (1)  we  find,  for  the  limit  of  tangential  action  (to  compare 
with  P=51,150  for  the  section  in  front  of  the  chamber)  : 

P =49, 130  pounds  per  square  inch. 

The  value  which  P  would  have  when  the  extension  6  became  imiform  through- 
out the  wall  is  found  from  equation  (3),  viz,  P=40,320,  and  the  corresponding 
value  of  the  uniform  extension  from  equation  (2)  is  0=21,554.  Observe  in 
this  case  that  the  values  of  P  and  d  for  this  particular  state  of  action  are  both 
greater  than  for  the  corresponding  state  for  the  thicker  section  in  front  of  the 
powder  chamber  where  P=38,910  and  0=17,067. 

CHARACTERISTICS  OF  THE  RESISTANCE  OF  CYLINDERS  DEPENDING  UPON  RADIAL  DIMEN- 
SIONS   AND    MODE   OF   CONSTRUCTION. 

It  will  be  seen  that  the  values  of  P  from  equation  (1)  for  the  limit  of  tangen- 
tial action  decrease  with  the  thickness  of  the  wall,  while  those  of  P  from 
equation  (3)  involving  the  uniformity  of  strain  increase  as  the  thickness 
decreases.  This  may  be  readily  seen  also  from  an  inspection  of  the  equations, 
and  if  we  should  plot  the  loci  of  the  values  of  P,  considering  Ro  as  a  variable 
with  successively  increased  values,  from  equations  (1)  and  C3)  the  two  lines 
would  intersect  within  the  limits  of  the  wall.  The  value  of  the  radius  Ro 
corresponding  to  this  point  of  intersection  where  the  two  values  of  P  are  equal 
marks  the  interior  radius  of  a  cylinder  (supposing  Rj  to  remain  16  inches  and 
the  constants  0  and  p  as  before)  in  which  the  extension  is  uniform  and  equal  to 
the  limit  (6)  35,000  when  P  has  its  maximum  value  for  the  limit  of  tangential 
action.  In  a  cylinder  with  such  interior  radius  the  whole  of  the  metal  would 
be  worked  to  its  tengential  limit  and  there  would  be  a  maximum  utilization  of 
the  metal  in  the  resistance  offered  to  an  interior  pressure. 

To  make  the  case  more  general,  let  us  find  the  value  of  the  ratio  £^=b  such 

that  d  shall  be  uniform  throughout  the  wall  and  equal  to  its  maximum  value 
when  P  is  a  maximum  for  any  cylinder. 
The  two  equations  of  condition  are  (1)  and  (2)  ;  we  must  equate  the  value 

R 

of  P   from  these  and  find  ^.     Placing  the  values  of  P  from  (I)  and  (2)  equal,  we 

have: 


'     LVRoy        J      4Rf+^Rg  ^    ^^> 


Substituting  b  =  =J  and  reducing 

^^^-^=    2^l'^'+2    ^^  +  ^^ 

whence  b  '-    ^^  +  ^  b'  +  0.5  b*  + -^- =  0 (12) 

29  29 


106  GUN    MAKING    IN    THE    UNITED   STATES. 

From  this  equation,  substituting  p  =  40,000,  and  0  =  35,000,  we  find 

b  =  2.4722. 
This  value  applies  to  the  particular  case  in  question  where  0  =  35,000  and  p  = 
40,000.     If  we  retain  Rj  =  16,  we  have  R^  =  ^  =  6.472  inches  or  a  bore  of  12.94 

inches,  and  a  thickness  of  wall  of  9.53  inches  instead  of  12  inches,  as 
originally  considered  in  the  section  in  front  of  the  chamber.  With  this  new 
value  of  Ro  and  given  constants  we  find  the  value  of  P  from  either  of  equations 
(1),  (2),  or  (3)  to  be  43,490  pounds.  The  maximnm  resistance  is  of  course 
decreased  (from  51,150  pounds)  by  this  decrease  of  the  thickness,  but  the  given 
ratio  determines  the  least  weight  of  metal  that  will  withstand  an  interior  press- 
ure of  43,490  pounds,  and  also  indicates  the  most  economical  use  of  the  metal 
considering  the  tangential  limit  of  extension  alone.  If  the  interior  radius  be 
fixed,  as,  for  instance,  Ro  =  4.75  (chamber  section)  we  find  R,  =  b  X  4.75  = 
11.743,  or  a  cylinder  with  9.5  interior  and  23.49  exterior  diameter  should  support 
this  pressure  of  43,490  pounds. 
If  0  =  p,  equation  (12)  becomes  : 

b3  -  2b2  +  0.5  b^  +  0.  5  =  0 (13) 

and  from  this  we  find, 

b  =  2.2946. 

R 
Then  in  any  case,  if  &  =  p,  the  ratio  :^  =  2.3  will,   if   Rq  or    R,    be    assumed, 

Ro 
fix  the  dimensions  of  a  cylinder  (made  with  full  initial  tension  or  assembled 
under  such  shrinkage  that  the  compression  of  the  bore  shall  equal  p),  which  will 
give  a  maximum  resistance  to  tangential  extension  for  the  least  weight  of  metal. 
From  this  value  of  b  we  find  the  thickness  of  the  wall  expressed  in  terms  of 
the  interior  radius : 

b  =  5^  =  2.2946 

Rq 

and  Ri  —  Ro  =  1.2946  Rg. 

If  the  walls  were  thicker  than  1.8  Ro,  the  condition  of  uniform  extension 
expressed  by  equation  (3)  would  be  reached  before  the  resistance  of  the  gun 
was  fully  developed;  if  the  wall  were  of  less  thickness  than  1.3  Ro  the  state  of 
uniform  extension  could  not  be  reached  without  the  tangential  extension  exceed- 
ing the  limit  6. 

The  values  of  P  which  we  have  just  discussed  would  cause  the  radial  com- 
pression at  the  surface  of  the  bore  to  be  exceeded  in  the  state  of  action.  Based 
on  this  limit  the  value  of  P  for  the  chamber  section,  derived  from  equation  (4) 
would  be  38,156  pounds  to  compare  with  a  similar  value  of  38,710  pounds  for 
the  section  in  front  of  the  chamber.  It  will  be  generally  considered  safest  and 
best  not  to  subject  a  gun  to  pressures  much  exceeding  the  value  of  P  here 
indicated. 

If  we  equate  the  values  of  P  from  equations  (1)  and  (4)  we  can  determine  a 

R 

value  for  the  ratio  =J  such  that  the  limits  of  tangential  extension  and  of  radial 

tin 


GUN   MAKING   IN    THE   UNITED    STATES.  lOT 

compression  would  be  simultaneously  reached  in  the  state  of  action.    We  have, 
supposing  p  =  e,  from  equations  (1)  and  (4) 

3(Rf-Rg)  (^  I  ^N-  2(Rf-Rg) 
4  Rf  +  2Ro  ^'  ^    '         2  Rf  -  Ro  ' 

R 

Making  p  =  6,  and  reducing,  also  placing  — 1  =  C; 

3  2 


2C='  +  1      2C^-1 
whence  C  =  v/5=  1.581, 

Or,  in  terms  of  the  thickness  and  the  interior  radius, 

R^  —  R„  =  0.58  Ro. 

From  this  last  it  appears  that  if  the  thickness  of  wall  exceeds  0.58  Ro,  the 
cylinder  will  first  fail,  in  action,  from  radial  compression  and  the  theoretically 
safe  value  of  P  would  be  derived  from  equation  (4).  If  the  thickness  were  less 
than  0.58  Ro  the  cylinder  would  fail  first  from  tangential  extension,  and  equa- 
tion 1  would  be  applied  to  find  the  value  of  P.  These  discussions  will  be  under- 
stood to  refer  to  a  cylinder  having  full  initial  tension  or  more  generally  to  a 
built-up  gun  in  which  the  tube  is  compressed  to  the  limit  in  the  state  of  rest. 

If  we  consider  a  simple  cylinder  without  initial  tension  the  limit  of  safety 
would  always  first  be  passed  under  tangential  extension  when  subjected  to  an 
interior  pressure  only.  The  equations  which  give  the  pressure  to  be  safely  sup- 
ported in  this  case  are  for  tangential  extension  and  radial  compression,  respec- 
tively.    (See  p.  6,  Note  35)  : 

pn\  _3(Ri  —  Rq)  fl  p^a\  _  3(Rt  —  Rq)  _ 

^  ''  ~  4  Rf  -+-  2  Rg    '  ^'       4R|-2Rg' 

Since  the  denominator  of  the  first  exceeds  that  of  the  second  in  the  sum  of 
4R3  and  since  6  is  for  the  metals  used  in  gun  construction,  either  equal  to  or 
less  than  p,  the  safe,  that  is  the  least  value  of  P,  will  be  found  from  the  first 
equation  which  corresponds  to  the  limit  of  tangential  resistance. 


Appexdix  C. 

ALLEGED    FAILURES    OF    STEEL   GUNS. 

The  following  is  in  reply  to  the  statements  made  in  Appendix  C  of  a  report 
adopted  by  the  Chamber  of  Commerce,  New  York  City,  February  3,  1887,  in 
regard  to  "  Failures  of  steel  guus." 

The  statement  publisfied  in  the  aforesaid  report  does  not  include  a  single 
authenticated  case  of  disastrous  failure  of  a  gun  representing  the  modern  type 
of  huilt-up  steel  guns  such  as  are  now  'being  made  in  the  United  States.  And  a' 
large  majority  of  the  cases  cited  refer  to  guns  which  were  made  largely  of 
v^rought  iron.  Herewith  follows  the  fourteen  (14)  separate  cases  of  alleged 
"failures  of  steel  guns,"  contained  in  the  report  of  the  Chamber  of  Commerce 
together  with  a  counter-statement  of  each  case  prepared  from  official  or  other 
authentic  source  of  information.  And  it  may  be  remarked  that  the  source  of 
information  used  in  preparing  the  report  of  the  Chamber  of  Commerce  has  been 
found  to  be  frequently  the  first  sensational  accounts  of  the  affairs  published  in 
newspapers,  sometimes  through  the  instrumentality  of  rival  business  firms. 

(1)  The  6-inch  gun  aboard- the  Active. 

Six-inch  steel  gun ;  burst,  using  half  a  charge  of  powder ;  investigation  by 
boards  could  not  explain  it.  (H.  M.  S.  Active.) 
This  was  not  a  steel  gun.  It  was  an  English  construction,  now  abandoned, 
comprising  a  steel  tube  reinforced  with  a  wrought  iron  coiled  piece.  The  gun 
burst  in  the  unhooped  portion  of  the  chase.  It  was  a  gun  designed  some  five 
years  since,  and  made  too  light  in  the  chase.  The  cause  of  the  failure  has  been 
sufficiently  explained  by  the  order  since  adopted,  to  place  hoops  upon  the  chase 
of  all  guns  like  it. 

(2)  The  gun  aboard  the  Canada. 

Gun  burst,  killing  one  man  and  wounding  four  others.     (H.  M.  S.  Canada.) 
The  cause  of  this  accident  was  a  premature  explosion  of  the  charge,  which 

occurred  before  the  breechblock  was  properly  closed. 

It  involved  no  fault  of  the  material  of  the  gun.     The  gun  was  not  burst,  only 

the  charge  was  blown  through  the  breech  to  the  rear. 

(3)  The  12-inch  gun  of  the  ColUngwood. 

Twelve-inch  steel  rifle  burst  with  3-4  charge,  221  pounds  of  powder,  714-pound 
shot;    tube  burst  8  feet  from  muzzle   and   split   the  pocket.     (H.   M.    S. 
Colling  loood.) 
The  ColUngtcood  guns  were  not  steel  guns.     They  were  an  English  construc- 
tion, now  abandoned,  consisting  of  a  steel  tube  reinforced  by  several  mild  steel 
coils  in  front  of  the  trunnions  and  by  a  coiled  wrought-iron  jacket  and  breech 
piece.     A  considerable  portion  of  the  muzzle  end  of  the  tube  was  not  hooped, 
and  was,  moreover,  but  2i  inches  in  thickness  at  the  neck  of  the  chase.     The 
tube  broke  in  front  of  the  hooping,  but  it  has  since  been  demonstrated  that  the 

108 


GUN    MAKING    IN    THE    UNITED    STATES.  109 

steel  (of  old  manufacture)  was  inferior  in  quality,  and  that  the  tube  forging 
had  not  been  annealed  after  oil  tempering.  These  guns  failed  primarily  because 
of  bad  methods  of  treating  the  steel,  and  again  because  they  were  of  weak 
construction  generally. 

(4)   The  100-ton  Armstrong  gun. 

One  hundred-ton  Armstrong  gun  burst  on  the  Italian  ironclad  after  a  very  few 
rounds.     (Duillo.) 
The  100-ton  Armstrong  gun  which  failed  aboard  the  Duillo  consisted  of  a  thin 
steel  tube  reinforced  by  wrought-iron  coils.     In  firing  the  gun  the  coils  parted 
at  the  joints,  and  the  steel  tube  being  left  unsupported  broke  away  with  them. 

(5)  The  1-inch  Armstrong  gun. 

Seven-inch  Armstrong  gun  burst  on  Argentine  vessel  (Pavonia) . 

This  is  undoubtedly  a  mistake.  The  accident  noted  perhaps  refers  to  a  gun 
built  of  wrought  iron  and  steel.  Reports  state  that  a  6-inch  Armstrong  gun  of 
this  character  aboard  the  Argentine  vessel  Parana  was  found  to  be  cracked  in 
the  tube.     There  was  no  bursting.    The  gun  was  replaced  by  the  maker. 

(6)  Bombardment  of  Alexandria. 

Some  of  the  guns  failed  at  the  bombardment  of  Alexandria.     (Alexandria.) 

There  were  no  modern  steel  guns  of  large  caliber  aboard  the  ships  at  Alex- 
andria. All  were  muzzle  loaders,  of  Frazier  system  of  construction.  A  40- 
pounder  Armstrong  was  the  heaviest  steel  gun  aboard  the  fleet.  The  sum  of 
the  failures  amounted  to  a  cracking  of  the  tube  in  one  or  more  of  the  large 
muzzle  loaders  (old  style). 

(7)  One  hundred-ton  Armstrong  guns. 

All  the  100-ton  guns  furnished  the  Italian  Government  by  Armstrong  &  Co. 

have  been  condemned,  although  none  of  them  have  been  fired  50  rounds. 

{Duillo,  Dandolo,  Lepanto.) 

These  l(X)-ton  Armstrong  guns  are  made  of  wrought  iron  and  steel.     We  do 

not  know  how  many  of  these  failed,  but  the  sole  cause  of  failure  arose  from 

defective  jointing  in  the  bore  of  the  two  parts  which  compose  the  tubes  of  these 

guns.     Nothing  in  the  failures  tells  against  steel.     Moreover,  it  is  believed  that 

the  guns  are  still  in  service. 

(S)   Four  teen-inch  rifle. 

Four  14-inch  rifles  of  latest  design  in  English  service  failed  in  July  last. 
(Ajax.) 
The  so-called  failure  of  the  guns  on  the  Ajax  consisted  simply  in  a  damaged 
vent.  This  was  repaired,  and  the  guns  continued  in  service.  Moreover,  it  was 
an  old  construction,  and  not  the  latest  design  at  all.  xVgain,  the  heaviest  gun 
aboard  the  vessel  was  12-inch,  designed  in  1871. 

(9)   The  100-ton  steel  gun. 

One  hundred  ton  steel  gun  blew  off  its  muzzle  at  the  proving  ground  at  St. 
Chamond,  Venice. 
This  probably  refers  to  a  75-ton  French  gun,  in  which  a  short  piece  of  the 
unhooped  portion  of  the  muzzle  is  said  to  have  been  broken  off  in  flring  at 


110  GUN    MAKING    IN   THE    UNITED   STATES. 

Ruelle,  France,  but  the  gun  was  not  thereby  rendered  unserviceable.  Certainly 
at  the  time  of  this  accident  there  had  been  no  100-ton  French  steel  guns  made. 
Nor  was  the  gun  that  failed  hooped  to  the  muzzle,  as  is  now  practiced. 

(10)   Tico  120-ton  steel  Krupp  guns. 

Two  120-ton  steel  Krupp  guns,  made  for  the  Italian  Government  for  coast 
defense,  failed  in  proof  and  were  not  accepted.     (Spezzia.) 

This  statement  is  directly  contradicted  in  a  letter  written  by  Mr.  Krupp, 
dated  November  5, 1886,  to  United  States  Consul  Potter,  of  which  the  following  is 
an  extract:  "  In  none  of  these  four  guns  (referring  to  the  whole  lot  ordered  by 
Italy)  has  the  slightest  defect  been  traced:  on  the  contrary,  even  No.  19464  of 
these  guns,  which  had  fired  82  rounds,  partly  with  considerably  heightened 
charges,  is  in  completely  fit  state  for  any  service." 

The  report  of  the  failure  of  these  guns  was  propagated  by  a  rival  firm. 

It  is  known  that  three  of  the  four  guns  have  been  accepted  by  the  Italian 
Government,  and  are  now  at  Spezzia.  Italy,  awaiting  emplacement  in  the  forti- 
fications. These  guns  were  shipped  by  Krupp  in  September.  1886,  and  before 
being  shipped  were  subjected,  respectively,  to  9,  11,  and  12  proof  rounds  each 
at  Krupp's  works.  The  fourth  gun  was  not  taken  by  Italy  and  Krupp  has  a 
fifth  gun  in  course  of  completion  to  fill  the  original  order.  This  fourth  gun  has 
been  retained  by  Krupp,  and  iised  by  experimental  firings  to  test  powders — the 
proof  having  been  continued  as  stated  above  to  the  number  of  82  rounds,  the 
gun  still  remaining  in  serviceable  condition.  The  eightieth  round  was  fired  with 
a  charge  of  847  pounds  of  powder  and  a  projectile  weighing  2,315  pounds,  giving 
the  measured  pressure  of  19.5  tons  per  square  inch  with  the  Rodman  gauge, 
and  18.765  tons  with  the  crusher  gauge,  an  initial  velocity  of  1,900  feet  per  sec- 
ond, corresponding  to  57,933  foot-tons  of  muzzle  energy,  and  a  penetration  of  41 
inches  of  iron  at  the  muzzle,  or  39.4  inches  at  1,094  yards.  In  regard  to  the  con- 
dition of  this  gun  after  the  eighty-second  round,  Krupy's  firing  record  states 
that  there  is  no  enlargement  of  the  bore,  and  that  in  the  powder  chamber, 
originally  93.03  inches  in  length,  a  maximum  elongation  of  1  mm.,  or  0.04  of  an 
inch,  nearly,  has  been  observed. 

{11)   The  6-inch  Navy  gun. 

One  6-inch  steel  rifl.e  at  the  Washington  Navy-Yard,  for  the  new  cruiser,  con- 
demned for  defects  found  in  the  bore  upon  final  inspection,  and  two  out  of 
five  guns  of  same  class,  show  similar  defects  in  the  hares.     (U.  8.  Navy.) 
There  was  but  one  gun  condemned  for  this  cause,  and  that  gun  was  taken 
apart  in  order  to  use  the  sound  pieces  in  the  construction  of  a  new  gun. 

(12)   The  8-inch  Army  gun. 

The  neic  S-inch  steel  rifle  made  for  United  States  Ordnance  Department,  of 

Whitworth  steel,  showed  enlargement  of  the  tube  after  twenty-four  rounds, 

so  that  firing  teas  suspended  and  the  gun  taken  to  the  machine  shop  to  be 

reenforced  by  additional  hoops.     (U.  S.  Army.) 

This  8-inch  United  States  Army  gxm  is  an  experimental  gun.     The  necessity 

for  chase  hooping  was  anticipated  before  any  firing  was  done.    The  enlargement 

of  the  bore  did  not  injure  the  gun  for  any  future  service,  and  has  been  corrected 

by  hooping  the  chase.     Seventy-seAcn  rounds  have  been  fired  from  the  gun  since 

the  chase  hooping,  and  there  is  no  sign  of  any  weakness  or  defect.     The  tube 

used  in  this  gun,  which  was  the  only  part  of  the  metal  that  indicated  weakness 


GUN   MAKING   IN    THE   UNITED    STATES.  Ill 

in  the  first  state  of  the  gun,  was  procured  from  abroad,  and  its  manufacture 
was  not  supervised  by  the  Department. 

,  (IS)  Krupp  guns  at  the  siege  of  Paris. 

At  the  siege  of  Paris  more  than  half  of  the  heavy  Krupp  guns  failed  during  the 
first  fortnight  of  the  bombardment,  and  during  the  Franco-Prussian  war 
more  than  200  Krupp  guns  burst.     (Major  Haig,  in  a  report  read  before 
the  Royal  Artillery  Institution.) 
We  will  note,  in  the  first  place,  that  no  heavy  guns — that  is,  seacoast  guns^ 
can  be  included  in  this  statement:  and  for  the  rest,  it  is  wholly  denied  by 
a  letter  written  by  Mr.  Krupp  in  1878.     His  letter  stated  that  of  the  17,000 
of  his  guns  made  between  the  years  1847  and  1878  only  18  had  failed   (about 
1   per   1,000),    and   those   failures   had    been    mainly    in   experimental    firings 
to  extremity,  or  on  account  of  the  square  angles  in  the  slot  made  for  the  breech- 
block, which  defect  he  had  remedied  in  his  later  guns.    Finally,  the  report  refers 
to  steel  guns  made  more  than  sixteen  years  since. 

To  this  it  may  be  added  that  a  carefully  prepared  table,  made  up  in  Italy, 
records  the  failure  of  but  11  Krupp  guns  between  1864  and  1882. 

(14)   Gun  in  after-barbette  of  Collingwood. 

The  Admiralty  Gazette  says:  "*rhe  bursting  of  the  J/S-ton  gun  on  board  the 

CoUivgirood  startled  the  country.    But  the  Naval  Annual,  recently  issued 

by  Lord  Brassey,  discloses  the  astounding  fact  that  '  similar  guns  in  the 

after-barbette  of  the  ColUngicood  have  been  since  tested,  and  one  of  them 

burst  ichen  fired  with  a  charge  of  poiodcr  of  about  two-thirds  the  weight 

of  that  used  in  the  trials  of  the  guns  in  the  fore-barbette.'     This  has  been 

carefully  kept  quiet  Hitherto,  and  should,  unquestionably,  be  investigated 

by  the  ordnance  inquiry  commission.'''     (Army  and  Navy  Journal.) 

In  the  Naval  Annual,  page  175,  there  is  simply  a  note  stating  the  well-known 

failure  of  the  single  Collingwood  gun,  namely,  that  in  the  after-barbette.    This 

case  is  the  same  as  that  referred  to  in  reply  (3).    There  was  only  one  gun  burst, 

and  that  instance  was  published  everywhere. 

In  preparing  the  foregoing  replies  every  endeavor  has  been  used  to  reach  a 
fair  statement  of  the  facts,  by  a  reference  to  the  files  of  the  Office  of  Naval 
Intelligence  in  cases  wherever  necessary.  In  summarizing  the  whole  number  of 
cases  it  is  seen  that  no  instance  is  cited  where  a  modern  steel  gun  has  failed  to 
such  an  extent  as  to  render  it  unfit  for  service.  The  French  gun  in  which  the 
muzzle  was  blown  off  was  an  all-steel  gun,  but  was  not  hooped  to  the  muzzle,  and 
the  gun  was  continued  in  use  by  facing  up  the  muzzle  end  of  the  tube.  Moreover, 
the  companion  guns  of  this  model  were  shortened  for  service  to  the  length  of 
the  one  with  which  the  accident  occurred ;  this  was  adopted  as  an  alternative 
to  muzzle  hooping.  Except  this  case  there  are  but  three  others  in  the  list,  viz: 
The  llG-ton  Krupp.  the  6-inch  navy,  and  the  8-inch  army  guns,  q.  v.,  which  refer 
to  modern  steel  guns ;  that  is,  four  cases  out  of  the  fourteen.  The  case  of  the 
Krupp  guns  at  the  siege  of  Paris,  q.  v.,  whatever  of  truth  there  may  be  in  the 
flatly  contradictory  statements  made  on  either  side  is  not  one  with  which  we 
are  now  concerned.  The  case  of  the  second  Collingwood  gun  (14)  is  an 
undoubted  canard.  There  remain  eight  more,  all  of  which  refer  to  combined 
wrought-iron  and  steel  guns,  both  breech  and  muzzle  loading,  and  out  of  these 
we  can  find  only  three  cases  in  which  the  guns  were  burst,  viz :  The  6-inch  on 
the  Active,  one  12-inch  on  the  ColUngicood,  and  100-ton  Armstrong  on  the 
Duillo. 


112  GUN   MAKING   IN   THE   UNITED  STATES. 

This  conclusion  receives  confirmation  from  an  official  return  submitted  to  the 
Parliament  of  Great  Britain,  dated  Januai-y  29,  1887 :  "  Showing  the  number, 
description,  name  of  designer,  place  of  manufacture,  and  position  at  the  time, 
of  the  rifled  iron  and  steel  guns  that  have  burst  or  been  temporarily  disabled 
through  defective  construction  or  from  other  causes  in  the  land  and  naval 
services  from  1875-76  to  1885-86."  This  list  contains  a  total  of  12  breech- 
loaders and  19  muzzle-loaders  of  all  calibers.  It  includes  but  three  breech- 
loading  guns  of  6-inch  caliber  or  above,  viz,  the  Active  and  Colling icood  guns 
and  one  7-inch  Armstrong  gun  burst  at  Sandown  Fort.  October  14,  1882.  These 
guns  were  all  admittedly  of  a  weak  construction  now  entirely  abandoned  in 
England,  and  their  failure  has  no  bearing  whatever  upon  the  question  of  the 
endurance  of  modern  steel  guns. 

N.  B. — The  very  erroneous  impressions  conveyed  in  the  report  of  the  chamber 
of  commerce  as  to  the  endurance  of  cast-iron  rifles  pure  and  simple,  and  their 
mistake  in  confounding  the  tubed  guns  with  simple  cast-iron  guns  (see  their 
Appendix  D)  have  been  shown  elsewhere  in  this  paper. 


A  Discussion  on 
Gun  Making  in  the  United  States 


REPRINTED  FROM  JOURNAL  OF  THE 
MILITARY  SERVICE   INSTITUTION 


113 

7733—08 8 


A  DISCUSSION  OF  CAPT.  ROGERS  BIRNIE'S  PAPER  ON  "GUN  MAKING  IN 
THE  UNITED  STATES."" 

Lieut.   Commander  F.   M.   Barber,    U.   8.   Kavy. 

Gentlemen  :  Captain  Birnie's  very  exhaustive  and  correct  treatment  of  the 
subject  leaves  nothing  to  be  said  except  in  the  way  of  praise.  The  year  1887 
will  be  memorable  in  the  history  of  gun  making  in  the  United  States  from  the 
fact  that  never  before  have  the  advocates  of  the  different  material  for  and 
methods  of  gun  manufacture  appeared  before  the  various  professional  societies 
of  the  country  and  laid  before  these  judges  the  variety  of  information,  theory, 
and  fact  in  possession  of  each  for  comparison. 

Commencing  with  the  Dorsey  paper  before  the  Naval  Institute  in  January, 
we  have  had  that  of  Mr.  Metcalf  before  the  Society  of  Civil  Engineers,  that  of 
Mr.  Morgan  before  the  Society  of  Mechanical  Engineers,  renewed  discussion  of 
Mr.  Metcalf's  paper  in  the  Society  of  Civil  Engineers,  the  paper  of  Mr.  Cowles 
before  the  Naval  Institute,  and,  finally,  that  of  Captain  Birnie  before  the  ]Mili- 
tary  Service  Institution. 

At  the  close  of  the  discussion  before  tlie  Society  of  Civil  Engineers  Mr.  INIet- 
calf  (who  is  an  ardent  and  able  advocate  of  steel-cast  guns)  paid  a  high  tribute 
to  the  ability  and  knowledge  displayed  by  our  ordnance  officers  of  the  Army 
and  Navy  and  congratulated  the  community  on  the  fact  that  otticers  had  at 
last  been  drawn  out  of  their  shells  and  had  given  the  public  the  benefit  of  their 
information.  I  think  that  in  coming  out  of  his  .^licll  Captain  Birnie  has  shown 
himself  in  this  paper  to  be  the  largest  sized  Government  moUusk  that  has  yet 
appeared  in  print.  His  assertions  are  supported  by  official  records,  his  theories 
are  sound  and  are  demonstrated  by  mathematical  calculations  that  are  irre- 
futable, and  they  are  proved  by  experimental  observation  of  the  most  elaborate 
character.  The  conclusion  which  he  draws  that  the  built-up  forged  steel  gun, 
which  has  been  adopted  by  both  Army  and  Navy,  is  at  the  present  day  the  best 
gun  both  from  the  manufacturer's  and  an  artillerist's  point  of  view,  seems  to 
be  perfectly  sound  and  inevitably  deducible  from  the  facts  in  the  case. 

His  mathematical  discussion  of  the  steel-cast  gun  and  the  line  of  practical 
investigation  which  should  be  followed  in  order  to  develop  its  greatest  possi- 
bilities is  new  and  particularly  interesting,  in  view  of  the  fact  that  there  are 
still  many  people  in  the  United  States  who  believe  that  the  true  solution  of 
the  great  gun  problem  is  to  be  found  in  making  it  of  one  piece  of  unforged  cast 
steel.  In  connection  with  this  matter  it  is  to  be  noted  that  within  the  weelv  the 
newspapers  have  reported  the  bankruptcy  of  the  "  Compagnie  des  Fonderies  et 
Forges  de  Terre  Noire,"  in  France,  a  wealthy  company  that  a  few  years  ago 
employed  more  men  than  any  other  in  the  world,  Krupp's  not  excepted.  This 
firm  made  a  specialty  of  unforged  cast  steel,  but  were  never  able  to  get  beyond 
hoops  in  even  small-sized  guns.  They  were  the  most  famous  firm  in  the  world 
for  this  kind  of  work  and  their  process  has  been  adopted  wit^j  success  by  the 

o  Read  before  the  Military  Service  Institution  at  Governors  Island,  New  York 
Harbor,  November  26,  1887,  and  printed  in  Monograph  VIII. 

115 


116  GUN    MAKING   IN    THE    UNITED   STATES. 

Swedish  Government  at  Bofors  for  making  solid  steel  suns  up  to  4  inches  in 
diameter.  Above  that,  however,  to  G  inches  the  guns  are  hooped ;  beyond  that 
they  do  not  go  at  all. 

The  present  published  condition  of  the  6-inch  steel-cast  guns  of  the  United 
States,  referred  to  by  Captain  Birnie  on  page  65,  is  as  follows :  "  The  Bessemer 
gun  has  been  successfully  cast ;  it  is  solid,  and  is  now  being  rough  bored.  The 
open-hearth  gun  is  to  be  cast  hollow  on  the  Rodman  principle,  but  the  attempt 
has  not  yet  been  made.  It  may  be  interesting  to  tabulate  the  physical  char- 
acteristics thus  far  published  regarding  tlie  metal  of  the  Bessemer  gun  and 
those  required  and  obtained  by  the  Naval  Bureau  of  Ordnance  in  the  tubes  and 
hoops  of  the  6-inch  forged-steel  guns  made  at  Midvale."' 

Specifications  as  bid  for  Bessemer  gun :  Tensile  strength,  80,000 ;  elastic  limit, 
40,000 ;  elongation,  7  per  cent. 

Published  as  obtained  after  casting  (unofficial):  Tensile  strength,  95,000; 
elastic  limit,  50,000;  elongation,  12  per  cent. 

Midvale  tube,  after  treatment  (official)  :  Tensile  strength,  80.000;  elastic  limit, 
35,000  ;  elongation,  22  per  cent. 

Midvale  hoops,  after  treatment  (official)  :  Tensile  strength,  96.000;  elastic 
limit,  47,000 ;  elongation,  15  per  cent. 

The  effect  of  treatment  is  to  increase  the  tensile  strength  and  elastic  limit 
and  to  diminish  the  elongation,  the  latter  by  about  one-third  or  one-fourth,  and 
the  Bessemer  gun  would  not  appear  to  have  elongation  enough  even  before 
treatment.  It  is  to  be  hoped  that  the  Military  Institute  will  be  able  to  obtain 
and  publish  with  this  discussion  the  I'esults  of  the  official  tests  soon  to  be  made 
of  the  specimens  talcen  from  different  parts  of  the  Bessemer  gun. 

Captain  Birnie's  paper  forms  a  fitting  closing  to  the  copious  discussions  of 
the  year  and  will  furnish  a  final  and  convincing  proof  to  the  manufacturing 
community  that  the  constituted  authorities  of  the  Army  and  Navy  know  what 
they  want  in  gun  metal  and  how  to  use  it  after  thej"  obtain  it. 

Brevet  Brig.  Gen.  H.  L.  Abbot,  Colonel,  Corps  of  Engineers. 

Captain  Birnie  has  compressed  into  small  space  a  very  instructive  statement 
of  the  results  of  a  series  of  experiments  scattered  through  a  term  of  years  and 
not  heretofore  easy  of  access.  It  is  no  small  service  to  bring  into  one  picture 
the  tombstones  of  past  failures  and  to  group  them  in  a  manner  to  indicate  where 
the  path  of  safety  for  the  future  is  to  be  found.  This  he  has  done,  and,  I  trust, 
in  a  way  to  carry  conviction  to  disinterested  minds.  It  is  time  to  recognize 
that  there  is  such  a  thing  as  a  science  of  gun  making  and  that  certain  theories 
which  a  quarter  of  a  century  ago  were  worthy  of  experimental  investigation  are 
no  longer  so  to-day. 

As  an  engineer,  I  am  specially  interested  in  the  experiments  with  mortars  in 
progress  at  Sandy  Hook.  There  can  be  no  doubt  that  this  weapon  is  destined 
to  play  a  more  important  part  in  the  defense  of  our  coasts  than  heretofore.  It 
has  been  developed  abroad  under  the  name  of  Howitzer  until  a  gain  of  fully 
200  per  cent  in  effective  force  of  impact  and  a  gain  of  upward  of  300  per  cent 
in  length  of  effective  range  have  been  secured.  The  cost  of  manufacture,  and 
especially  of  emplacement,  is  small  as  compared  with  that  of  guns.  The  Foi'ti- 
fication  Board,  of  which  Secretary  Endicott  was  president  in  1886,  recommended 
724  heavy  mortars  and  581  high-power  guns  of  all  calibers  for  the  defense  of  our 
entire  seacoast.  Evidently  the  development  of  the  best  pattern  and  mode  of 
construction  is  a  matter  of  the  highest  importance ;  and  it  is  earnestly  to  be 
hoped  that  the  Ordnance  Department  is  not  to  be  hampered,  as  heretofore,  in 
other  directions,  by  the  pressure  of  interested  parties  urging  their  own  wares 
upon  the  attention  of  Congress. 


GUN   MAKING  IN   THE  UNITED   STATES.  117 

While  heartily  concurring  in  most  of  the  views  expressed  by  Captain  Birnie  in 
this  interesting  paper,  I  am  constrained  to  dissent  from  his  estimate  of  the 
practical  value  of  the  pneumatic  gun  in  coast  defense.  Its  short  range  restricts 
its  fire  to  the  area  obstructed  by  submarine  mines,  and  we  'can  not  afford  to 
make  every  shot  which  misses  the  enemy  a  countermine  to  destroy  them,  and 
thus  open  a  route  for  his  passage.  The  mines  are  indispensable,  because  steam 
vessels  can  force  their  way  through  any  unobstructed  channel  under  cover  of 
darkness,  whether  the  projectiles  thrown  at  them  contain  gunpowder  or 
dynamite ;  and  we  can  not  inti'oduce  a  new  weapon  that  directly  antagonizes 
another  of  prime  importance  which  it  can  not  replace. 

If  it  be  suggested  that  the  use  of  the  "  aerial  torpedo  "  may  be  restricted  to 
the  period  of  the  siege  when  the  submarine  mines  having  been  destroyed  by  the 
enemy,  he  is  ready  to  attempt  to  pass  the  forts,  we  must  call  to  mind  that  this 
invention  is  more  nearly  allied  to  a  mortar  than  to  a  gun  in  the  character  of  its 
trajectory.  Although  an  advocate  of  the  use  of  vertical  fire,  where  properly 
applicable,  I  draw  the  line  where  the  target  is  in  rapid  motion.  When  the 
channel  is  once  opened  the  ships  will  pass  at  full  speed,  and  it  will  be  of  little 
use  then  to  assail  them  with  any  kind  of  mortar  projectile.  Outlay  invested  in 
these  pneumatic  guns  could,  in  my  judgment,  be  better  spent  for  other  means  of 
defense. 

The  weapon  rests  its  claim  for  introduction  into  service  upon  its  exclusive 
ability  to  throw  high  explosives  with  safety ;  but  it  is  stated  on  good  authority 
that  mortar,  shells  charged  with  110  pounds  of  wet  gun  cotton  are  even  now  fired 
successfully  in  Germany,  and  improvements  in  the  compositions  of  high  explo- 
sives is  making  so  rapid  progress  that  there  is  reason  to  expect  an  early  use 
for  them  even  in  guns.  Under  these  circumstances  I  think  the  company  has 
done  wisely  in  preferring  to  bring  thQir  invention  to  the  attention  of  the  Navy 
rather  than  to  that  of  the  Army.  As  a  counterminer  to  destroy  submarine  mines 
it  may  have  value,  although  without  actual  proof  I  should  be  loth  to  assume 
that  it  could  do  more  than  moderately  assist  in  the  opening  of  that  Icnown  and 
well-defined  channel  from  Jf  to  6  miles  long,  without  which  no  armored  ship 
will  safely  pass  our  forts.  The  gallantry  of  our  enemies  is  assumed,  but  there 
will  be  conspicuous  need  for  it  in  maneuvering  an  unarmed  floating  magazine, 
containing  many  tons  of  dynamite  under  the  fire  of  modern  high-power  guns 
mounted  on  land  at  a  range  of  1  or  2  miles. 

Brevet  Maj.  J.  B.  Campbell,  Captain  Fourth  Artillery. 

Captain  Birnie's  paper  begins  by  mentioning  the  period  of  brief  superiority  in 
ordnance  that  the  genius  and  industry  of  Rodman  and  Dahlgren  vouchsafed  the 
United  States,  and  laments  the  decline  in  the  art  of  gun  making  in  our  country, 
except  in  the  direction  of  small  arms  and  machine  guns. 

He  pointedly  remarks  that  for  the  inception  and  proof  of  the  principles  and 
practice  of  gun  construction  now  acknowledged  to  be  fundamentally  correct,  the 
world  is  indebted  to  citizens  of  the  United  States,  and  leaves  it  to  be  inferred 
that  the  want  of  support  and  development  of  these  practices  in  our  country  is 
due  to  want  of  appropriations  by  Congress. 

He  doubts  the  advisability  of  changing  the  direction  or  control  of  armament 
construction  from  that  of  personal  responsibility,  assisted  by  a  body  of  life- 
long oflicers,  trained  for  their  business  at  Government  expense,  to  any  other 
plan,  and  hopes  that,  in  any  event,  the  decision  of  the  question  lohat  guns  the 
Army  shall  use  will  be  intrusted  to  military  men.  If  by  military  men  he  means 
those  who  are  to  use  the  guns  in  repelling  danger,  he  will  have  a  large  following. 
It  will  be  otherwise  if  the  term  is  construed  to  mean  the  noncombatant  corps 
of  designers,  constructors,  and  inspectors  that  has  heretofoi'e  controlled  this 


118  GUN    MAKING    IN    THE    UNITED   STATES. 

question.  Looking  beyond  the  United  States,  it  will  be  ol)served  that  almost  all 
of  the  really  great  progress  in  gun  making  has  taken  place  in  countries  that  have 
no  national  foundries  and  gun  shops,  and  no  exclusive  corps  of  ordnance 
designers  and  manufacturers.  In  fact,  the  nations  who  were  not  encumbered 
with  the  latter  were  the  first  to  derive  benefit  in  their  armament  from  the 
ingenuity  and  skill  of  private  inventors  and  manufacturers.  Whitworth  and  the 
Elswick  works  in  England  occupy  the  attention  of  the  world  rather  than  the 
national  establishment  at  Woolwich,  and  the  latter  has  been  successively  driven 
from  almost  every  one  of  its  assumed  positions  by  the  superior  practice  and 
productions  of  the  finest  establishments. 

Krupp  and  Grusen  are  the  dependence  upon  which  the  Government  of  their 
country,  as  well  as  several  foreign  ones,  rely.  France,  accepting  through  defeat 
and  humiliation  the  lesson  taught  her  liy  the  national  patrons  of  private  enter- 
prise, realized  that  the  official  exclusiveness  and  perfunctory  ruts  of  the 
national  shops  and  foundries  of  Gavre,  Bourges,  Ruelle,  and  Nevers  were  a  poor 
reliance  in  the  supreme  moment,  and  called  to  her  aid  in  the  necessity  for  reor- 
ganization and  rearmament  the  science,  skill,  emulation,  and  progress  of  St. 
Etienne,  Le  Creusot,  and  St.  Chamond. 

Austria,  with  her  Vienna  establishment,  her  Yon  Lenk  and  Von  Uchatius.  and 
their  years  of  official  failures,  wholly  or  in  part,  has  followed  the  example  of  her 
more  youthful  and  progressive  neighbor,  Italy,  and  now  gets  her  armament 
where  it  can  be  best,  most  successfully,  and  cheaply  made. 

In  Russia  only  do  government  establishments  appear  to  prosper  and  produce 
acceptable  material.  It  is  a  question  whether  this  is  not  to  be  attributed  to  the 
purely  despotic  and  personal  government,  where  the* sovereign's  will,  unimpeded 
by  turbulent  scheming  and  pipe-laying  legislatures  says  tvhat  shall  be  done,  how 
it  shall  be  done,  and  irho  shall  do  it.  It  is  for  the  Czar's  interest  and  safety  to 
get  the  best  attainable  to  serve  him  in  all  capacities,  and  he  does  it.  Even  In 
Russia,  following  the  general  rule,  government  works  are  mere  imitators. 
Rarely  if  ever  are  original  conceptions  produced  by  public  functionaries. 

A  small  gun  shop  for  experiment  and  investigation  would  probably  be  a  desir- 
able plant  for  the  United  States  to  possess,  but  the  Government,  whose  chief  and 
only  mission  should  be  to  make  and  administer  the  laws  and  protect  the  country 
from  exterior  and  interior  harm,  should  never  be  a  manufacturer  or  enter  into 
any  other  kind  of  business,  fo-r  the  simple  reason  that  in  competition  with 
private  enterprise  it  falls  behind  and  becomes  extravagant;  this  will  ever  be  the 
case  as  long  as  a  hired  agent  is  inferior  to  a  principal.  The  vitality  and  progress 
inspired  by  successful  competition  and  supported  by  the  acumen  necessary  to 
avoid  the  expense  of  failure,  can  not  be  exijected  of  those  whose  existence  is 
equally  comfortable  in  failure  or  success.  Let  the  Government  othcers  select  the 
gun  best  suited  for  the  purposes  desired — or  invent  it,  if  they  can — inspect  the 
material  of  which  it  will  be  made,  superintend  if  you  will  the  work  of  con- 
struction (although  I  believe  neither  of  these  are  done  in  Europe),  and  test  it 
when  completed  ;  but  let  the  American  manufacturer  make  it. 

The  running  history  of  guns,  both  conceived  of  and  made,  is  very  interesting 
and  instructive,  accurate,  and  as  full  as  could  be  made  in  the  narrow  limit  of  an 
evening  lecture. 

The  explanation  of  the  principles  of  construction  of  built-up  steel  guns  i» 
clearly  and  concisely  put,  and  should  go  far  to  convince  all  of  the  fact  that  such 
guns,  when  they  are  properly  designed,  and  when  the  mechanical  construction 
accurately  and  faithfully  follows  the  design,  are  within  reach,  powerful,  reliable, 
and  safe,  no  matter  what  may  be  said  of  other  guns.  The  worst  that  can  be  said 
against  them  is  the  great  difficulty  in  accomplishing  the  minute  mechanical 
accuracy  of  design  that  is   indispensable  to  the  safety  and  perfection  of  the 


GUN    MAKING   IN    THE    UNITED    STATES,  119 

system  in  such  large  masses  of  metal ;  and  of  securing  within  them  the  desirable 
uniformity  of  required  or  assigned  physical  properties.  The  liability  of  latent 
interior  defects  in  the  masses  has  practically  disappeared  with  the  introduction 
of  improved  metallurgic  methods,  and  in  the  latest,  or  De  Bange  development 
of  the  system,  wherein  by  decreasing  the  dimensions  and  proportionally  multi- 
plying the  number  of  the  masses,  their  homogeneity  is  rendered  more  certain, 
the  strength  of  the  gun  is  increasetl,  and  the  cost  of  the  plant  necessary  to 
manufacture  them  is  decreased.  Captain  Birnie  has  been  a  faithful  student  of, 
and  an  untiring  investigator  in,  the  interesting  problem  of  the  development  of 
the  built-up  steel  gun.  and  his  modesty  has  concealed  the  fact  that  both  the 
science  and  art  of  building  steel  guns  on  the  principle  of  initial  tension  owe  not 
a  little  to  his  industry  and  ability. 

The  steel  wire-wrapped  guns  of  Longridge,  Woodbridge,  Schultz,  and  Arm- 
strong may  really  be  considered  as  the  ultimate  development  of  the  hooped  or 
built-up  gun.  The  perfect  interior  state  of  the  walls  of  a  gun,  as  far  as  initial 
strain  is  concex-ned,  can  be  made  to  more  nearly  and  surely  approach  theoretical 
requirement  by  wire  winding  them  than  by  any  other  way.  This  construction 
is  receiving  attention  in  all  countries  interested  in  gun  problems,  and  it  is  hoped 
experiAents  with  it  will  not  cease  in  the  United  States.  While  it  is  not  con- 
demned by  Captain  Birnie,  he  says  little  to  encourage  what  he  admits  to  be  a 
promising  problem. 

Captain  Birnie,  strong  in  his  faith  and  admiration  of  wrought-steel  tubes, 
jackets,  and  frets,  courageously  attacks  the  rationality  of  attempting  cast  or 
homogeneous  steel  gun  constructions.  In  these  days  of  rapid  development  of 
the  possibilities  of  metallurgy  it  is  dangerous  to  predict  what  can  not  be  done. 
But  a  few  years  ago  it  would  have  been  thought  madness  to  undertake  to  make 
a  steel  casting  approximating  in  size  to  a  5-inch  gun.  To-day  .such  a  casting 
is  an  accomplished  fact,  and  the  faith  of  its  artisans  in  its  inherent  goodness 
of  quality  and  strength  is  almost  as  great  as  is  that  of  Captain  Birnie  in  his 
forgings.  France  and  Italy  have  extensive  and  powerful  armaments  consisting 
of  cast-iron  guns  tubed  and  fretted  with  wrought  steel.  It  is  within  possibility 
that  a  vastly  better  gun  could  be  made  by  substituting  cast  steel  for  cast  iron 
in  such  a  combination,  and  it  does  not  require  a  superabundance  of  credulity 
to  expect  to  see  initial  strain  as  surely  and  accurately  engendered  within  a 
homogeneous  steel  gun  as  in  a  built-up  one.  Such  an  achievement  would  not 
be  nearly  as  great  an  advance  as  has  been  made  in  the  science  of  gun  construc- 
tion within  the  last  fifteen  years.  Official  conservatism  must  be  kept  out  of 
danger  of  getting  into  a  traveled  rut.  The  trials  and  triumphs  of  Sir  Henry 
Bessemer  should  ever  be  a  warning  restraint  against  unconsidered  disapproval 
of  the  ideas  of  intelligent  specialists  and  investigators.  It  is  useless  to  say  that 
the  steel  built-up  gun  marks  the  limit  to  improvement  in  ordnance  with  steel 
as  the  material  to  be  used,  and  equally  unwise  to  believe  or  assert  that  another 
metal  or  metallic  alloy  may  not  be  found  that,  under  proper  treatment,  will 
relegate  steel,  with  all  its  noble  and  surprising  properties,  as  far  to  the  rear  in 
the  gun-making  world  as  its  intimate  neighbors,  cast  and  wrought  iron,  have 
been. 

Joseph  Morgan,  Jr.,  Esq. 

So  much  has  been  written  upon  the  subject  of  our  proposed  new  ordnance, 
and  the  very  complete  and  able  resume  of  Captain  Birnie  covers  the  ground 
so  thoroughly,  there  is  nothing  more  to  say.  The  work  in  direction  of  new 
steel  guns  has  been  so  well  done  by  our  ordnance  officers  that  I  hope  they  may 
be  allowed  appropriations  to  continue  it.     My  own  views  on  this  subject  are 


120  GUN   MAKING   IN   THE   UNITED  STATES. 

well  known.  Whether  our  guns  cost  10  cents  or  $1  per  pound  is  not  material, 
provided  they  are  the  most  powerful  tools  of  the  kind  to  be  had. 

I  believe  forged  and  tempered  steel  of  high  elastic  limit,  properly  assembled 
by  shrinkage,  gives  the  best  guns  known. 

If  material  with  an  elongation  of  7  to  10  per  cent  and  reduction  of  area  5  to  7 
per  cent,  with  an  elastic  limit  of  40,000  and  ultim:.te  of  80,000  is  accepted,  as  in 
naval  cast  guns  now  under  contract,  why  not  use  forged  steel  of  80,000  elastic 
limit,  135,000  ultimate,  which  has  equal  ductility,  and  raise  the  powder  pressure, 
getting  greater  range  and  penetration? 

Theodore  Cooper,  Esq. 

In  Appendix  B  the  author  in  his  investigation  makes  an  assumption  which 
is  a  very  common  one,  but  which  is  an  erroneous  one,  viz,  that  a  metal  having 
an  elastic  limit  of  40,000  pounds  per  square  inch,  as  determined  by  the  usual 
method  of  applying  one  kind  of  strain  (tension  or  compression)  from  the  zero 
point  of  strain,  can  be  subjected  to  alternating  strains  of  +40,000  pounds  to 
— 40,000 ;  or,  in  other  words,  that  the  compressive  force  p  and  the  tensile  force  d 
can  each  be  worked  to  or  near  the  above  ordinary  elastic  limit. 

Such  a  belief  has  been  long  prevalent  and  is  still  persistent.  Many  of  the 
mysterious  failures  of  our  machines  and  structures  are  due  to  this  false  doctrine. 

In  1867  Herr  Wohler  made  a  very  valuable  series  of  experiments  upon  iron 
and  steel  subjected  to  continued  changes  of  strain  of  various  kinds.  These 
experiments  were  first  published  in  English  in  Engineering,  1871,  March  to  June. 

From  the  results  of  these  tests  he  concludes  "  that  variations  of  strain  may, 
with  equal  security,  take  place  within  the  following  limits,  it  being  of  course 
assumed  that  in  all  cases  the  maximiun  strain  is  less  than  that  required  to  pro- 
duce fracture  under  a  stated  load :  " 

1.  Bars  subjected  to  tension  and  compression : 

Iron +17, 120  pounds  to  —17, 120  pounds. 

+35.  310  pounds  to  0  pounds. 

+47,  080  pounds  to  +25,  G80  pounds. 
Cast  steel  for  axles +29,960  pounds  to  —29,960  pounds. 

+51,  360  pounds  to  0  pounds. 

+85,  600  pounds  to  +37,  450  pounds. 
Untempered  cast  steel  for  springs  +53,  500  pounds  to  0  pounds. 

+  74,900  pounds  to  +26,750  pounds. 

+85,  600  pounds  to  +42,  800  pounds. 

+9G,  300  pounds  to  —64,  200  pounds. 

2.  Bars  subjected  to  shearing  strains  : 

Cast  steel  for  axles +28,540  pounds  to  — 23,540  pounds. 

+40,  660  pounds  to  0  pounds. 

Although  these  experiments  extended  over  years  and  some  of  the  test  pieces 
were  subjected  to  as  high  a  number  of  tests  as  1.32,000,000,  it  nmst  not  be 
assumed  that  the  above  limits  ai"e  exactly  determined  even  yet.  They  do.  how- 
ever, show  that  the  capacity  of  a  piece  of  metal  to  resist  different  kinds  of 
strains  is  variable. 

The  explanation  usually  adopted  is  covered  by  the  term  "  fatigue  of  metals," 
to  my  mind  a  very  unscientific  and  ab.surd  expression. 

Upon  reading  the  I'eport  of  these  tests  when  first  published  it  seemed  to  me 
that  a  much  more  probable  explanation  was  that  the  position  of  the  elastic  limit 
moved  and  should  be  measured  from  the  initial  strain;  that  the  term  "range 
of  elasticity  "  would  be  more  applicable.     For  example,  in  the  case  of  his  iron. 


GUN    MAKING   IN    THE   UNITED    STATES,  121 

the  elastic  range,  until  we  approach  the  breaking  limit,  would  be  about  35,000 
pounds,  whether  measured  from  — 17,000  or  from  0. 

To  assume  that  a  material  having  an  elastic  limit  of  35.000  pounds  would 
ultimately  break  down  under  strains  not  exceeding  one-half  of  this  amount  on 
the  fatigue  theory  would  violate  all  conception  of  a  perfect  elasticity. 

Whereas  to  accept  the  idea  that  our  material  did  have  an  clusiic  range  equal 
to  35.000  pounds,  which  must  be  measured  between  the  extreme  limits  of  our 
strains,  is  perfectly  in  harmony  with  a  perfect  elasticity. 

In  a  recent  number  of  Engineering,  November  25,  1S87,  I  find  that  Profes- 
sor Bauschinger  has  made  a  series  of  experiments  on  the  alteration  of  the  elas- 
tic limit  of  iron  and  steel,  extending  over  several  years. 

He  concludes  upon  the  point  under  discussion  that  "  the  elastic  limit  in  ten- 
ision  is,  in  general,  very  different  from  that  of  the  material  when  subjected  to 
compression  and  artificially  raising  the  elastic  limit  in  tension,  causes  the  limit 
In  compression  to  be  decreased,  and  this  may  even  pass  through  the  point  of 
zero  stress.  In  other  words,  a  bar  of  steel  or  iron  has  two  elastic  limits,  and 
whatever  position  these  occupy  on  the  scale  of  loads,  the  range  between  them 
is  nearly  a^constant  quantity.  By  alternately  stretching  a  bar  in  tension  and 
compression  just  beyond  the  elastic  limits,  these,  after  a  certain  number  of 
repetitions,  occupied  positions  equally  distant  from  the  point  of  zero  load,  and 
the  limits  thus  obtained  are  called  by  Bauschinger  the  natural  elastic  limits  of 
the  bar.  It  was  then  noted  that  the  stress  corresponding  to  these  limits 
sensibly  coincided  with  that  found  by  Wohler  as  the  limiting  stress  to  which 
a  bar  could  be  subjected  to  alternate  tension  and  compression.  It  would  thus 
appear  that  a  bar  will  bear  an  indefinite  number  of  repetitions  of  stress,  pro- 
vided the  I'ange  of  stress  does  not  exceed  the  elastic  range  mentioned  above." 

This  is  a  perfect  confirmation  of  the  views  I  have  held  for  years,  and  is  a 
satisfactory  explanation  of  what  is  usually  called  the  fatigue  of  metals. 

Holding  this  belief,  I  do  not  think  the  compression  at  the  bore  plus  the 
expected  tension  should  exceed  the  elastic  range  of  the  material  if  the  strains 
as  determined  by  the  ordinary  formula'  are  correct. 

This  would  lead.  I  suppose,  to  a  less  initi;il  comiu-ession  at  the  bore  and  also 
a  less  tension  at  the  exterior. 

And  if  the  strains  from  temperature  are  considered,  a  still  fui'ther  reduction 
would  be  needed.  For  a  lineal  dilatation  of  0.0012  for  180°  F.,  and  a  modulus 
of  elasticity  of  30,000,000,  each  10  degrees  of  difference  of  temperature  between 
the  surface  of  the  bore  and  the  exterior,  would  cause  a  new  strain  of  2.000 
pounds  per  square  inch  additional  difference  of  strain  between  the  interior  and 
exterior. 

How  much  such  difference  of  temperature  would  amount  to  I  leave  to  those 
better  able  to  judge,  though  I  would  expect  it  to  be  consideral)le  in  rapid  firing 
of  heavy  guns. 

I  leave  to  those  who  are  better  posted  in  the  application  of  the  theoretical 
formulae  to  determine  in  what  manner  these  views  may  affect  the  design  and 
construction  of  guns. 

It  is  very  doubtful  to  my  mind  whether  the  theoretical  strains  due  to  the  hoop- 
tension  theory  will  obtain  in  practice.  I  should  expect  somewhat  the  same 
failure  of  correspondence  between  the  theory  and  practice,  as  we  find  in  the 
fiber  stress  of  solid  metal  beams  under  the  analogous  theory  of  elastic-beam 
liexure. 

.1.  R.  Ha.skell^  Esq. 

Captain  Birnie,  in  his  criticism  on  the  multichai'ge  gun.  says :  "  Of  the  various 
experiments  made,  we  have  accounts  of  the  performance  of  three  guns  only, 
viz,  a  2i-inch  gun  tested  at  the  Washington  Navy- Yard,  a  6-inch  gun  tested  at 


122  GUN    MAKING    IN    THE    UNITED   STATES. 

Keadiiiir,  I'a..  in  1870.  and  tlie  G-in<-li  sun  wliieli  was  tested  at  Sandy  Hook." 
Captain  Birnie  knows  nothinj;  about  the  many  otbev  experiments  made  with 
multieharge  giuis. 

I  commenoe<l  making  and  experimenting  with  these  guns  in  connection  with 
Mr.  A.  S.  Lyman  in  185o,  and  we  worked  in  concert  until  I8r>o,  since  which 
time  he  has  not  been  connected  with  it.  He  is  now  dead.  These  experiments 
liave  cost  over  $300,000  of  private  capital,  and  have  consumed  years  of  time. 
I  never  asked  a  dollar  of  Government  aid  until  I  had  demonstrated  the  success 
of  the  multieharge  principle. 

In  1857,  through  the  friendship  of  Gen.  Winfield  8cott  and  at  his  request,  I 
obtained  permission  to  test  a  2i-inch  accelerating  or  multieharge  gun  (which 
I  had  constructed)  at  the  Water  Battery  at  West  Point.  In  1857  and  1858  I 
made  many  experiments  there.  I  bad  previously  experimented  with  guns  of 
different  calibers,  and  made  on  different  plans,  but  all  embracing  the  accelerat- 
ing principle. 

The  first  official  test  was  made  at  Fortress  Monroe,  ^'a.,  in  1858,  before  a 
board  of  artillery  officers,  of  which  Col.  H.  Brown  was  president.  I  conducted, 
all  these  experiments  in  person. 

It  was  after  this  that  the  2i-inch  bore  gun  was  made,  which  was  tested  at 
the  navy -yard.  Washington,  in  18G3.  Captain  Bii-nie  says  this  gun  "  penetrated 
a  target  of  wrougbt-iron  plates  5  inches  thick,  backed  by  18  inches  of  solid  oak 
timber.  This  gave  a  penetration  of  '  more  than  2  calibers.'  The  firing  was  done 
at  200  yards,  with  a  total  charge  of  Gf  pounds  of  powder  and  a  steel  projectile 
weighing  19f  pounds." 

Captain  Birnie  does  not  state  the  whole  case.  This  target  had  been  fired  at 
three  times  before  by  a  5-inch  Whitworth  gun.  which  was  unable  to  penetrate 
entirely  through  the  5-inch  iron  plate,  and  the  gun  was  cracked  at  the  third 
discharge.  The  2^-inch  multieharge  gun  was  then  put  at  the  same  place.  The 
first  shot  fired  did  not  strike  true,  but  "  wabbled,"  the  shot  breaking  and  stick- 
ing in  the  iron  plate.  The  second  shot  struck  fair,  penetrated  entirely  through 
the  target  and  backing,  making  a  hole  of  about  its  own  diameter,  and  struck  the 
water  some  distance  in  the  rear. 

Subsequently  the  same  gun  was  tried  against  a  target  representing  a  section 
of  the  original  monitor  turret,  made  of  the  same  kind  of  iron,  and  formed  in 
the  same  machine  as  the  original  turret.  The  target  was  improperly  supported 
so  that  it  fell  when  struck  by  the  snot,  which  "  wabbled  "  some  and  did  not 
strike  fair.  The  shot  was  broken  in  the  target,  but  "  penetrated  7i  inches,  cut- 
ting a  hole  3  inches  by  ?>i  inches."  The  officer  in  charge  admitted  that  if  the 
shot  had  struck  fair,  and  the  target  had  been  jiroperly  secured,  the  shot  would. 
liMve  penetrated  entirely  through  the  target — 10  inches.  He.  however,  refused 
to  allow  another  shot  to  be  fired  at  it. 

At  that  time  no  gun  in  the  world  could  penetrate  more  than  1  caliber,  and 
lew  could  do  that.  Here  was  a  gun  which  actually  penetrated  3  calibers,  and 
which  it  was  admitted  could  penetrate  4  calibers.  What  encouragement  did  it 
receive?  Why,  the  olRcer  in  charge  (who  was  subseijuently  Chief  of  Ordnance 
of  the  Navy)  reported  the  above  facts,  and  then  remarked  "that  he  regarded 
the  gun  as  more  curicms  than  useful,  and  recommended  that  no  furtlier  experi- 
ments be  made  with  it." 

The  G-iuch  multieharge  gun  tested  before  the  Ordnance  Board  at  Sandy  Hook 
.was  made  of  very  poor  metal,  the  cast  iron  as  well  as  the  steel.  The  board 
reports,  "  It  is  admitted  that  the  6-inch  gun  is  made  of  inferior  metal."  The 
endurance  of  this  gun  would  therefore  he  no  criterion  by  which  to  judge  the 
system.  Besides,  the  gun  was  rifled  on  a  very  defective  system,  the  same  as 
that   now   used   in  the  new   steel   guns  of  the  Army  and  Navy.     This  system 


GUN    UtAKlNG    IN    THE    UNITED    STATES.  123 

requires  the  use  of  either  expantliug  or  "  slugging  "  projectiles,  i.  e..  where  the 
grooves  and  lands  of  the  rifling  are  imprinted  on  soft  metal  bands  at  the 
instant  of  discharge.  This  kind  of  projectile  creates  unnecessary  friction  in 
the  gun,  helps  to  destroy  it.  and  at  the  same  time  robs  the  shot  of  a  great 
portion  of  its  force. 

I  was  forced  to  adojit  this  system,  because  I  could  not  have  the  gun  rifled  as 
I  desired  by  contract,  and  the  treasurer  of  the  company  would  not  consent  that 
any  work  should  l)e  done  by  the  day.  Had  the  gun  been  properly  rifled  it  would 
have  had  much  greater  endurance  in  spite  of  the  defective  metal. 

Captain  Birnie  states  that  after  the  tube  was  cracked  "  bands  were  shrunk  on 
the  chase  of  the  gun,  the  only  part  where  the  form  of  the  gun  admitted  the 
employment  of  this  kind  of  strengthening." 

The  2^-inch  multicharge  gun  tested  at  Washington  had  wrought-iron  bands 
shrunk  over  the  pockets,  while  no  bands  were  put  on  the  chase.  One  of  the  forms 
of  multicharge  guns  I  have  designed  has  a  central  tube  and  the  balance  of  the  gun 
is  all  "  built  up  "  by  shrinking  on  bands.  The  built-up  plan  is  therefore  available 
for  multicharge  guns  as  well  as  for  single  charge,  and  they  can  be  made  equally 
strong.  I  do  not,  however,  approve  of  built-up  giuis.  I  have  much  better  and 
stronger  plans.  I  have  made  these  guns  in  many  different  ways.  Captain  Birnie 
has  only  seen  one  and  is  not  therefore  competent  to  judge. 

The  enormous  penetration  accomplished  by  the  one-half-inch  bore  model  I  made 
excites  the  attention  of  Captain  Birnie.  That  gun  penetrated  lOi  calibers  in 
wrought  iron  and  was  not  fvilly  charged  at  that.  The  same  gun  can  penetrate  12 
calibers.  It  was  made  to  prove  that  the  multicharge  system  could  be  carried  out 
to  almost  any  extent.  We  do  not  propose  to  make  large  guns  of  as  great  relative 
power.  If  we  did,  a  12-inch  gun  would  penetrate  12  feet  of  wrought  iron.  That 
is  more  than  is  necessary,  and  the  gun  would  be  very  long.  We  can,  however, 
with  guns  of  moderate  length,  penetrate  four  or  five  calibers,  or  double  as  much 
as  any  single-charge  gun  can  do,  and  with  less  pressure. 

The  power  developed  by  the  6-inch  multicharge  gun  at  Sandy  Hook  exceeded  • 
anything  ever  before  accomplished  by  any  gun  of  that  caliber,  and  with  less 
pressure,  as  the  official  reports  show. 

With  a  multicharge  gun,  the  breech  of  which  can  be  made  of  the  same  material 
and  as  strong  as  any  single-cliarge  gun,  the  same  charge  of  powder  can  be  used 
in  the  breech  if  desired,  and  with  the  same  effect.  After  that  additional  charges 
can  be  added  and  much  greater  results  achieved. 

Ca])tain  Birnie,  on  jiage  91.  sajs  the  range  of  the  G-inch  navy  gun  is  3,046 
yards  at  an  elevation  of  3°  10'.  The  range  of  the  6-inch  multicharge  gun  at  Sandy 
Hook  was  3,000  yards  at  an  elevation  of  2°  55',  iising  much  less  pressure  than  the 
naval  gun. 

The  range  of  the  Krupp  11-inch  gun  at  4°  54'  was  4,419  yards,  weight  of  pro- 
jectile 760  pounds,  weight  of  i)Owder  2.54  pounds.  (See  report  "  Board  on  Fortifi- 
cations and  other  Defenses,"  p.  45.)  The  range  of  the  6-inch  multicharge  gun  at 
4°  30'  elevation  was  4,480  yards.  Sixty-one  yards  greater  than  the  Krupp  gun, 
with  24'  less  elevation,  and  using  a  pressure  of  10,000  pounds  per  square  inch 
less  than  the  Krupp  gun. 

Captain  Birnie  closes  his  remarks  as  follows :  "  Most  emphatically,  then,  a 
higher  energy  has  not  been  obtained  with  this  gun  with  its  successive  charges  and 
with  moderate  and  safer  pressures  than  can  result  from  any  gun  of  the  same 
caliber  using  only  one  charge."  That  is  the  statement  of  Captain  Birnie,  who 
never  witnessed  an  experiment  with  a  multicharge  gun.  Against  this  I  quote  the 
statement  of  the  Ordnance  Board,  composed  of  officers  of  the  same  corps,  out- 
ranking Captain  Birnie,  and  of  much  greater  experience,  who  say  in  their  official 
report  on  the  multicharge  gun  trials  :  "  There  seems  to  be  no  doubt  that  a  higher 


124  GUN    MAKING   IN   THE   UNITED  STATES. 

energy  has  been  obtained  with  this  gun  with  its  successive  charges  and  with 
moderate  and  safer  pressure  than  can  resiilt  from  any  gun  of  the  same  caliber 
using  only  one  charge." 

T.  G.  Baylor,  Colonel  of  Ordnance.  President  of  Board. 
(Signed)  Geo.  W.  McKek,  Major  of  Ordnance. 

Charles  Shaler,  Captain  of  Ordnance. 

Note. — For  a  more  full  and  complete  answer  to  all  objections  to  the  multicharge 
system,  reference  is  made  to  a  paper  read  before  the  "American  Association  for 
the  Advancement  of  Science"  on  August  16,  1887,  by  J.  R.  Haskell,  which  has 
been  printed  in  pamphlet  form,  and  can  be  had  free  on  application  to  ^Ir.  Haskell. 

Capt.  Charles  Shaler,  Ordnance  Department. 

One  ix»int  made  in  Captain  Bii*nie's  paper  can  not,  I  think,  be  too  much  dwelt 
upon. 

Suppose  that  it  is  desirable  to  try  a  steel  gun  cast  in  a  single  piece,  why  should 
it  be  necessary  to  await  the  result  of  the  trial  before  commencing  to  build  guns 
equal  to  the  best? 

Nothing  is  more  certainly  proven  with  reference  to  guns  than  that  each  caliber 
must  be  tried  for  each  different  mode  of  construction.  The  history  of  gun  trials 
is  full  of  accounts  of  structures  which  have  answered  for  a  certain  caliber  and 
failed  for  a  greater  one. 

If  a  6-inch  steel  gun  cast  in  one  piece  prove  suitable  after  fabrication  and  trial, 
it  will  teach  us  but  little  as  to  higher  calibers.  The  larger  gun  must  be  made 
and  tried  before  similar  ones  can  be  issued  to  the  service.  All  this  requires  in 
each  case  increased  plant  and  more  time  for  experiment. 

The  most  powerful  pieces  in  existence  to-day  are.  without  any  question,  built-up 
guns.  A  course  of  costly  experiments  extending  through  years  has  shown  that  for 
each  caliber  used  the  method  is  good.  We  know  that  such  guns  can  be  constructed 
if  we  obtain  steel  possessing  certain  characteristics  declared  by  those  who  wish  to 
supply  the  material  in  this  country  within  limits  that  can  be  reached  by  them, 
because  such  material  has  been  made  in  Germany,  France,  and  England.  There 
is  no  peradventure  about  this,  no  careful  passing  from  the  known  to  the  unknown, 
no  questions  of  relying  on  the  statement  of  an  expert  that  he  can  do  what  has 
never  yet  been  done,  but  certainly  because  we  may  all  possess  a  knowledge  of  what 
has  already  been  done  frequently.  In  other  words,  did  the  Government  but 
possess  the  plant  for  fabrication  it  could  at  once  commence  to  supply  an  arma- 
ment to  defend  the  coast. 

We  do  not  know  positively  that  a  single  cast-steel  gun  will  answer  the  purpose. 
It  may  do  so.  and  if  we  are  to  wait  until  guns  are  made  of  all  the  materials  pro- 
posed, the  coast  will  never  be  armed.  Cast  steel  made  by  the  open-hearth, 
Bessemer,  crucible,  or  mitis  processes  has  been  advocated ;  so  has  aluminum 
bronze ;  so  has  a  mixture  of  the  cheapest  kind  of  pig  iron  "  refined  "  by  adding 
proper  proportions  of  copper,  lead,  and  mercury.  Wire  winding  is  urged,  and  so 
year  by  year  will  other  metals  and  methods,  good,  bad,  and  indifferent,  come  up. 

By  ail  means  let  them  be  tried  in  some  suitable  way,  but  when  we  know  to-day 
how  to  make  guns  equal  to  the  best  in  existence,  why  continually  delay  their 
manufacture  lest  something  else  may  prove  better. 

To  do  so  is  to  imitate  the  poet's — "  Fools  waiting  for  certainty." 

Lieut.  E.  M.  Weaver,  Second  Artillery. 

The  gun  users  look  at  this  question  of  gun  making  \vith  a  little  impatience. 
The'  gun   makers   in   this   country   have   been — as   Captain   Birnie's   account 
shows — experimenting    with  this,  that,  and  another  gun  design  for  a  score  of 


GUN   MAKING  IN   THE   UNITED    STATES.  125 

years,  working  along  cast-iron  muzzle-loading  lines,  then  cast-iron  breech-loading 
lines,  and  have  now  settled  down  on  what  Captain  Birnie  regards  as  the  ultimate 
stage  of  development,  in  so  far  as  design  is  concerned,  namely,  the  built-up  forged- 
steel  gun. 

Captain  Birnie's  advocacy  of  the  forged-steel  gun  is  certainly  as  emphatic  as  it 
could  well  be :  and  in  view  of  the  clouds — small  as  yet,  to  be  sure — on  the  horizon 
of  the  forged-steel  built-up  gun,  as  rejiresented  by  the  cast-steel  gun,  and  the  use 
of  aluminum  bronze  as  a  gun  metal,  he  is  surely  to  be  complimented  on  the  frank 
manner  in  which  he  states  his  opinion,  all  the  more  so  inasmuch  as  what  he  says 
will,  per  force,  be  accepted  as  the  Ordnance  view,  notwithstanding  the  disclaimer 
in  the  preface. 

The  Artillery  would  be  thankful  if  it  could  think  that  the  end  to  temporizing  in 
this  matter  had  been  reached ;  for  if  it  ever  come  to  be  a  fact,  we  may  expect  to 
have  a  few  first-class  guns  mounted ;  but  on  looking  back  our  confidence  is 
impaired,  for  we  recall  the  fact  that  there  has  from  time  to  time,  if  not  always, 
been  some  "  cock;Sure  "  idea  advocated  that  has  in  due  course  retired  before  a 
new  fancy. 

During  all  this  time  the  coast  has  been  without  protection  from  shelling,  and 
the  artillery  has  not  had  a  single  breechloader  of  larger  caliber  than  a  field  gun 
for  practice  purposes,  notwithstanding  the  fact  that  there  were  good  breech- 
loaders of  all  calibers  needed  for  a  secure  defense  on  the  coast  on  the  market, 
and  that  there  were  several  breechloaders  at  Sandy  Hook,  idle,  that  had  been 
sufficiently  tested  for  drill  purposes,  if  not  for  firing,  that,  considering  their 
breech  mechanism  alone,  would  have  been  a  blessing  as  an  object  lesson  to 
artillerymen  who  have  never  seen  a  breechloader  as  large  as  a  siege  gun. 

Captain  Birnie  places  the  responsibility  for  all  this  at  the  door  of  Congress; 
but  may  it  not  be  true  that,  if  the  Ordnance  Department  had  been  less  interested 
in  experiments,  and  more  alive  to  what  could  have  been  had  by  other  methods, 
Congress  would  have  been  more  liberal? 

It  must  be  admitted  that  there  has  been  no  time  within  the  period  under 
consideration  that  we  could  not  have  purchased  and  mounted  on  our  coasts 
guns  that,  for  each  epocli,  would  have  protected  our  cities,  and  thus  have  given 
some  return,  in  the  form  of  insurance  against  loss  of  property,  to  the  citizens 
who  pay  for  the  weapons.  It  seems  to  us  the  interest  of  the  citizens  of  our 
sea  ports  in  this  matter  demands  that  we  first  give  them  protection,  from  what- 
ever source  or  by  tchatever  methods  it  can  he  secured,  and  then,  after  having 
accomplished  this,  we  may  legitimately  experiment  with  a  view  to  developing 
home  gun  making. 

On  the  basis  of  this  home-manufacture  policy  our  seacoast  has  been  forced  to 
await  the  development  of  the  American  idea  in  gun  making,  which  has  been,  in 
practice,  the  Ordnance  idea.  And  what  is  the  result?  A  servile  adoption  of 
European  ideas  that  might  have  been  accepted  twelve  years  ago,  as  clearly  set 
forth  in  Commander  Simpson's  report  of  his  oflicial  visit  to  Europe. 

The  conditions  are  not  different  to-day.  There  are  several  gun  designs  claim- 
ing attention,  and  our  coasts  are  unprotected. 

The  guns  we  most  need  are  those  that  will  hold  off  the  largest  guns  afloat  to 
a  point  beyond  shelling  range  from  the  city  being  defended.  It  is  these  large 
guns  on  our  outside  line  of  defense  that  will  be  needed  within  a  hundred  hours 
after  a  declax'ation  of  war.  Such  guns  should  have  greater  ballistic  power  than 
any  gun  that  can  be  floated  against  them,  and  be  able  to  pierce  or  shatter  any 
armor  that  can  be  carried  into  our  waterways.  It  is  economy  to  mount  the 
largest  guns  that  can  he  secured,  for  the  larger  the  gun  the  greater  lead  we 
shall  have  over  armor  in  the  pending  race,  and,  by  anticipating  its  development, 
our  guns  will  be  longer  serviceable;  also,   since  the  effective  range  of  guns 


126  GUN    MAKING    IN    THE    UNITED   STATES. 

nsraiust  armor  incroasos  very  rapidly  with  increase  of  caliber,  and  tlie  area 
guarded  increases  as  the  square  of  the  effective  range,  larger  guns  mean  fewer 
guns  and  fewer  forts.  Comparing,  for  the  sake  of  illustration,  a  20-inch  with  a 
IG-inch  gun.  the  effective  range  of  the  former  is  seven  times  the  latter ;  the  area 
guarded  effectively,  forty-nine  times.  It  certainly  does  not  cost  forty -nine  times 
as  much  to  mount  a  20-iuch  gun  as  a  16-inch  gun. 

The  necessity  of  large  guns  has  been  made  imperative  by  the  present  and 
prospective  strength  of  steel  and  compound  armor;  we  believe  that  nothing 
below  1.500  foot-tons  projectile  energy  per  ton  of  plate  can  with  safety  be 
assumed  as  a  measure  of  plate  strength  for  ballistic  estimates. 

It  will  be  years  before  such  guns  can  be  supplied,  if  we  depend  on  past 
methods.  The  only  way,  it  seems  to  us,  to  secure  a  speedy  defense  of  the  coast 
on  the  outside  line  is  to  open  contracts  to  all  reputable  gun  makers  of  the 
world,  regardless  of  design,  provided  a  reasonable  safety  of  gun  is  guaranteed, 
with  modern  mechanical  appliances.  It  makes  little  difference  to  citizens  and 
artillerists  whether  a  gun  is  or  is  not  a  few  pounds  heavier  or  feet  longer  than 
another  gun,  if  it  gives  proper  bnllistic  results. 

It  would  be  a  calamity,  we  believe,  if.  to  arm  our  outside  line,  we  should  be 
forced  to  wait  for  the  gun  makers  of  built-up  forged-steel  gims  in  this  country 
to  creep  tentatively  through  the  stages  from  the  present  S-inch  standard  to  those 
calibers  absolutely  necessary  to  defend  our  cities  from  shelling. 

William   E.  Woodbridgi:,   Esi]. 

I  am  compelled  to  say  that  the  "  built-up  "  gun  finds  more  th.in  a  "  rival  "  in 
the  0.2-inch  Woolwich  steel-wire  gun,  which  has  imparted  to  its  pi'ojectile  of 
oS5.8  pounds  a  velocity  of  2.500  feet  per  second.  And  this  is  not  a  finality  in 
wire  gun  construction. 

We  need  guns;  and  I  would  not,  if  I  could,  hinder  the  production  of  guns  of 
the  Vavasseur  type.  But  we  must  not,  for  the  sake  of  uniting  in  a  voice  of  "  no 
uncertain  sound."  conceal  from  ourselves  the  truth.  While  its  structure  is  in 
great  measure  theoretically  correct,  the  principles  accepted  point  to  a  higher 
type.  As  yet  practical  proofs  of  the  strength  of  the  system  are  wanting.  High 
pressures  are  studiously  avoided.  As  yet,  it  must  be  said  (I  might  quote  good 
authority),  "we  are  building  our  guns  on  hypotheses  that  have  never  been  prac- 
tically verified."  Assembling  the  guns  with  tht;  most  correctly  estimated  shrink- 
ages and  under'  the  minutest  inspection  does  not  so  far  test  the  soundness  of  the 
material,  or  its  freedom  from  injurious  initial  strains,  that  it  may  not  leave  a 
hoop  at  the  point  of  rupturing  from  its  own  tension  or  a  tube  with  an  undetected 
tiaw  of  any  magnitude  not  apparent  upon  the  surface. 

It  is  impossible  to  make  heVe  the  corrections,  and  especially  the  additions  to 
the  statements  of  the  paper  concerning  wii-e  guns,  which  would  be  necessary  to 
afford  a  basis  for  a  full  consideration  of  their  merits.  I  add  a  few  words,  how- 
ever. The  10-inch  brazed  wire  gun  was  not  originally  intended  or  expected  to 
be  altogether  suitable  for  a  test,  but  (as  a  9-inch)  was  intended  "to  give  the 
necessary  experience  to  the  workmen  to  construct  the  12-incli  gun  determined 
on."     ("Ordnance  Report,"  1872,  p.  ITG.) 

The  powder  used  in  the  last  three  roimds  was  linown  to  be  of  especial  violence. 
In  the  words  of  the  board :  "  It  burst  into  two  parts  just  behind  the  trunnions 
under  a  powder  pressure  of  about  80.000  pounds  to  the  square  inch  measured  by 
the  Rodman  gauge."  Nothing  invalidated  the  indication  of  the  gauge  employed. 
The  rupture  was  in  a  plane  of  imperfect  brazing.  It  should  be  noted  that  the 
rear  portion  of  the  gun  actually  withstood  the  enormous  pressure.  The  only 
possible  question  as  to  the  strength  of  the  system  was  that  of  complete  brazing, 
all  reasonable  doubt  of  which  was  negatived  by  a  study  of  the  experiment  itself. 


GUN   MAKING   IN    THE   UNITED    STATES.  127 

When  a  "built-up"  gun  shall  liiiish  its  career  with  an  equal  exhibition  of 
strength  it  will  have  acquired  honors  not  yet  won  by  any  of  the  existing  or 
departed. 

As  a  correction  of  the  views  expressed  on  ]»n,L'e  ;'>(i,  in  the  iiara.^rraph  closing 
with  lines  in  italics,  I  refer  to  the  "  Report  of  the  Koard  on  Heavy  Ordnance," 
38S2.  page  17. 

I  think  it  necessary  to  avow  the  opinion  that  questions  of  national  armament, 
often  as  intricate  as  questions  of  law,  may  be  better  decided  by  a  "  full  bench  " 
than  by  a  single  judge,  however  competent  and  impartial. 

No  monopoly  of  (pialification  can  be  claimed  for  any  department  or  professitm. 
Till'  author,  who  has  made  ample  exhibition  of  his  learning  and  acquaintance 
with  the  theories  of  Lame  and  Clavarino,  offers  a  convenient  illustration  of  this 
statement,  by  an  error  which  might  be  serious  in  practice,  in  treating  theoret- 
ically of  the  increase  of  resistance  derived  from  a  linip.g  tube — on  pages  22  and 
23.  I  can  neither  quote  the  text  nor  hint  tlie  correction  here,  but  shall  trust  to 
the  ability  and  candor  of  the  author  to  make  the  correction.   ' 

I  question  whether  the  Army  may  prefer  that  the  production  of  guns  shall  be 
wholly  "  intrusted  to  military  men." 

Benjamin  Robins,  "the  fatlier  of  scientific  gunnei'y,"  was  a  civilian;  so  was 
Doctor  Hutton,  who  followed  up  his  work ;  and  Comit  Rumford,  who  investigated 
the  force  of  gunpowder;  so  also  the  first  to  measure  its  actual  pressure  in  guns; 
the  inventor  of  the  expanding  projectile ;  Treadwell,  Benjamin  Chambers,  Doctor 
Gatling,  Hotchkiss,  Parsons,  Vavasseur- — a  few  fi'om  a  long  list. 

In  lS.oO  we  had  here  the  (actual)  wire  gun — Treadwell's  excellent  guns;  the 
expanding  projectile,  proved  to  be  superior  in  accuracy  to  any  cluster  of  shots 
recorded  in  the  Ordnance  Department,  superior  in  penetration,  exploding  by 
percussion,  and  Chambers'  slotted-screw  fermeture.  There  was  needed  not  pro- 
fessional ordnance  skill  to  perfect  them  (that  is  not  always  its  tendency),  but 
a  competent  tribunal  to  weigh  their  value.  Such  a  tribunal,  selected  with  the 
greater  care,  from  military,  naval,  and  civil  life,  would  have  been  in  the  past, 
and,  I  judge,  would  in  the  future  be  of  the  greatest  service. 

I  take  this  opportunity  to  declare  my  high  appreciation  of  the  services  of 
officers  of  the  Ordnance  Department,  their  ability  and  character. 

Capt.   O.   E.  MiCHAELis,   Ordnance  Department. 

Captain  Birnie  certainly  merits  our  gratitude  for  doing  so  well  what  to  liim 
has  been  apparently  a  labor  of  love,  presenting  succinctly  a  resume  of  ordnance 
progress  in  the  United  States  since  1840.  His  presentation  is  clear  and 
unbiased.  His  own  decided  pi'edilections  control  only  when  bearing  upon  our 
latest  official  construction,  the  hooped  steel-forged  gun,  and  herein  he  certainly 
must  be  held  excusable,  for  we  may  well  say  of  him  in  connection  with  this  gun 
"  Quorum  magna  pars  fui."  The  time  limit  assigned  compels  me  to  be  brief,  and 
hence  my  remarls:s  can  necessarily  touch  but  few  points,  and  must  be,  in  addition, 
merely  suggestive. 

I  rejoice  to  see  that  Captain  Birnie  does  tardy  justice  to  that  wonderful  man, 
Daniel  Treadwell.  Some  fifteen  years  ago  I  had  the  privilege  of  examining 
some  of  his  unpublished  work,  and  I  felt  then  that  he  was  certainly  a  quarter  of 
a  century  in  advance  of  bis  time,  and  that  his  name  is  worthy  to  be  associated 
with  the  names  of  Bomford,  Dahlgren,  and  Rodman,  great  leaders  of  American 
ordnance  progress. 

In  discussing  the  subject  of  initial  tension,  the  experiments  of  Mr.  G.  Leverich, 
M.  Am.  Society  of  Civil  Engineers,  undertaken  in  1875,  while  he  w^as  in  charge 
of  the  construction  of  the  Thompson  gun,  should  not  be  forgotten.     He  was  the 


128  GUN    MAKING    IN    THE    UNITED   STATES. 

first  to   examine  the  tensions  of  successive  concentric  rings  from   interior  to 
exterior.     His  work  will  soon,  I  hope,  be  accessible  to  all  interested. 

The  hooped  forged  steel  gun,  so  far  as  military  authority  can  make  it  so,  is  at 
present  the  adopted  model,  arid  it  is  the  duty  of  all  navy  and  army  exports  to 
do  everything  in  their  power  to  make  it  a  practical  success. 

Still  this  sense  of  duty  can  not  affect  the  right  of  private  judgment.  Per- 
sonally I  do  not  believe  in  the  French  fermeture ;  the  objections  to  it  are  well 
known  and  need  not  be  iterated  here. 

Captain  Birnie  himself  appears  not  to  be  its  partisan,  and  I  agi'ee  fully  with 
him  that  in  the  present  state  of  our  metallurgical  plants  it  is  the  only  feasible 
closux'e  for  the  adopted  model  of  gun. 

Further,  I  am  an  avowed  enthusiastic  believer  in  the  thorough  trial  of  steel- 
cast  guns.  I  recommended  it  nearly  five  years  ago,  and  my  belief  in  its  feasi- 
bility has  strengthened  year  by  year. 

Krupp  is  the  cheval  de  hattaille  of  the  opposers  to  the  Government  trial  of 
great  steel-cast  guns.  His  array  of  21.000  successful  guns  is  showered  upon  us, 
until  we  are  apparently  buried  beyond  possibilitj'  of  exhumation. 

The  side  that  calls  liim  must  abide  by  the  whole  testimony  of  the  witness; 
there  is  a  well-known  legal  maxim  that  applies. 

The  hooped  forged-steel  guns  of  which  there  has  recently  been  question  with 
us,  differ  from  Krupp  guns  in  material,  principle  of  construction,  and  breech 
mechanism,  and  wheu  Krupp  guns  are  cited  in  support  of  our  present  construc- 
tion, I  can.  with  equal  logic,  cite,  in  support  of  my  views,  the  thousands  and 
thousands  of  successful  cast  guns. 

Krupp  uses  crucible  steel  at  present,  awaiting  the  impending  improvements 
in  the  open-hearth  process,  the  only  trustworthy  homogeneous  steel  made — a 
result  due  to  the  crucibles  being  solely  a  melting  pot  and  not  a  refining  appa- 
ratus. Krupp  does  not  make  a  liooiicd  forged  gun,  in  our  sense — he  makes 
mantle  or  jacket  guns.  His  underlying  principle  is  the  entire  removal  of  longi- 
tudinal strain  from  the  gun  tube.  His  field  guns  consist  of  but  two  parts,  the 
tube  and  tlie  mantle,  which  carries  trunnions  and  fermeture.  His  latest  con- 
structions, the  40-centimeter  monsters,  are  also  mantled  and  not  hooped.  Krupp 
uses  the  wedge  as  a  closure,  carried  independently  of  the  gun  body — we,  the 
screw,  necessarily  seated,  directly  or  indirectly,  in  the  body. 

The  Krupp  ingots  for  the  16-inch  gun  bodies  weighed  over  70  tons  each — 
pretty  fair-sized  guns  to  start  with. 

I  do  not  hesitate  to  announce  my  belief  that  the  main  heneflcial  effects  of  ham- 
mering such  a  mass  of  steel  lie  in  shaping  the  metal.  I  further  believe  that 
whatever  supposed  improvement  may  be  brought  about  in  its  physical  condition 
under  hammering  is  due  to  successive  heating  and  reheating.  I  am  fully  con- 
vinced that  steel  can  acquire  all  its  mechanical  properties  without  hammering, 
and  that  in  the  near  futui'e  we  shall  see  both  hannuer  and  press  used  simply  as 
economical  shapers. 

I  can  not  understand  why  there  should  be  such  opposition  to  the  thorough 
trial  of  steel-cast  guns.  Dahlgren,  Eodman,  and  Woodbridge  guns  have  been 
tried  at  Government  expense ;  why  not  then  steel-cast  guns,  every  step  in 
whose  fabrication,  whatever  be  the  outcome,  would  add  invaluable  knowledge 
to  our  metallurgical  manipulations? 

We  are  not  without  justifying  data  for  our  hopes  of  success.  Steel  is  a  curi- 
ous alloy — every  day  develops  new  features  in  production  and  behavior.  All  cast 
guns  have  been  successfully  made  and  tested  in  Sweden.  An  8.4-centimeter  gun, 
Krupp  model,  tube  and  jacket  both  cast,  has  been  fired  over  2,000  rounds  with 
charges  weighing  3^  pounds  and  projectiles  14J  pounds,  and  not  the  slightest 


GUN    MAKING   IN    THE   UNITED    STATES.  129 

enlargement  of  chamber  is  perceptible.  The  metal  was  38  carbon,  with  an 
elastic  limit  and  ultimate  tenacity  for  the  mantle  of  53,700  and  100,200,  for 
the  tube,  73,500  and  121.000,  which  shows  that  by  proper  treatment  cast  speci- 
mens can  be  made  to  indicate  any  desired  physical  propei-ties. 

I  fear  I  have  already  exceeded  my  time,  and  will  therefore  stop,  merely 
iterating  the  wish  that  the  authorities  would  lead  this  investigation  of  the  prac- 
ticability of  casting  steel  guns,  an  investigation  that  would  in  nowise  antagonize 
any  present  plans  of  gun  construction,  an  investigation  that  would  be  of  incal- 
culable advantage  to  what  promises  to  be  the  widespread  art  of  steel  founding. 

R.  H.  Thurston,  Esq. 

I  do  not  think  that  I  can  add  anything  valuable  to  the  mass  of  facts  presented 
by  Captain  Birnie.  It  is  a  paper  of  such  unusual  extent  and  richness  that  it 
could  hardly  be  expected  that  any  engineer,  not  a  specialist  in  that  field,  should 
be  able  to  offer  more  than  confirmatoi'y  sentiments  in  such  parts  of  the  subject 
he  might  be  somewhat  familiar  with. 

The  necessity  of  instant  action,  and  that  on  an  enormous  scale,  in  view  of  the 
exceedingly  critical  position  to  which  the  blindness  of  the  General  Government 
has  reduced  us,  must,  as  it  seems  to  me,  be  obvious  to  the  most  thoughtless  and 
least  patriotic  of  our  citizens.  I  am  not  sure  that  it  can  be  said  just  where  all 
the  responsibility  lies,  but  I  presume  that  it  is  mainly  with  the  Appropriation 
Committees  of  Congress,  and  especially  in  the  House  of  Representatives.  How- 
ever, that  is  not  the  vital  matter  at  the  moment ;  the  first  thing  to  be  done  is  to 
render  the  nation  safe  against  foreign  foes  at  the  earliest  possible  instant ;  and 
it  seems  tolerably  evident  that  much  must  be  done  in  educating  our  representa- 
tive bodies  up  to  a  point  from  which  they  may  be  able  to  form  some  faint  idea  of 
the  dangers  to  which  they  have  exposed,  and  to  which  they  are  still  exposing, 
their  country.  Once  Congress  is  fully  aware  of  the  situation,  it  is  probable  that 
less  will  be  said  of  a  visionary  "  surplus  "  in  the  Treasury,  and  more  of  its  expend- 
iture in  directions  in  which  it,  and  more,  should  long  ago  have  been  placed — 
coast  defense,  army  and  navy  material,  and  interior  and  frontier  improvements. 
Should  the  business  men  of  the  country  ever  take  active  part  in  matters  of 
national  importance,  and  work  hand  in  hand  with  the  legislative  bodies  and  with 
their  natural  advisers  of  the  two  branches  of  the  service,  we  may  cease  to 
apprehend  such  dangers  as  now  threaten  us ;  but  I  fear  not  vmtil  then.  It  is  at 
least  a  source  of  some  comfort  to  find  that  our  officers,  in  Army  and  Navy,  are 
doing  their  part,  however  much  our  legislators  may  neglect  their  highest  duty. 

I  find  myself  greatly  interested  in  the  paper  under  discussion,  both  as  giving 
valuable  and  often  new  information  and  as  representing  the  views  of  experi- 
enced and  thinking  officers  in  regard  to  the  best  materials  and  constructions  of 
modern  heavy  guns.  While  recognizing  the  difficulties  involved  and  the  com- 
parative imperfection  of  the  familiar  processes  and  apparatus  used  in  the  ijjanu- 
facture  of  large  masses  in  steel,  I  have  always  had  a  strong  conviction  that 
that  metal  would  completely  displace  iron  in  all  ordnance,  as  well  as  in  nearly 
all  constructions  of  other  sorts ;  and,  further,  that  ways  would  sooner  or  later 
be  found  to  handle  it  in  the  largest  masses  that  might  be  called  for  and  to 
give  it  its  highest  qualities  whatever  their  magnitude.  We  evidently  are  still 
a  long  way  from  the  ideal  state  of  the  art  to  which  we  aspire ;  but  we  are  as 
evidently  making  continuous  and  somewhat  rapid  progress.  The  built-up  gun 
must  obviously  precede  the  solid  in  heavy  ordnance;  and  the  approach  to  the 
ideal  construction  seems  to  me,  in  the  light  of  existing  knowledge  and  experi- 
ence, to  be  likely  to  come  rather  through  the  gradual   increase  in  size  and 

7733—08 9 


130  GUN    MAKING    IN    THE    UNITED   STATES. 

•decrease  in  number  of  parts  of  the  built-up  gun  than  through  the — in  some 
respects — opposite  course  illustrated  by  Treadwell  and  Woodbridge.  It  would, 
however,  be  folly  to  dogmatize  in  that,  as  in  any  other  matter  of  engineering. 
The  built-up  gun  is  certainly  to-day  the  representative  of  the  highest  modern 
art  in  ordnance  construction.  The  introduction  of  oil  hardening  and  tempering 
is  an  enormous  step  in  advance ;  and  the  systematic  ways  now  in  vogue  of 
testing,  experimenting,  and  scientifically  determining  the  quality  of  the  metal, 
as  variously  treated,  and  of  ascertaining  the  line  in  which  further  progress 
must  be  made,  are  sure  to  give  us  safe  and  sure  guidance.  The  history  of  this 
progress,  as  presented  by  Captain  Birnie,  is  an  exceedingly  interesting  one, 
valuable  not  only  as  a  record  of  the  past,  but  as  guide  for  the  future.  In  the 
light  of  these  systematically  collected  and  arranged  masses  of  knowledge,  such 
as  are  here  illustrated,  it  is  to  be  hoped  and  fully  expected  that  we  may  in 
time  come  to  the  construction  of  the  heaviest  of  ordnance  in  single  masses,  or 
in  few  pieces,  in  such  manner  as  to  bring  out  the  very  highest  possible  qualities 
of  metal  in  the  best  possible  gun. 

I  have  no  doubt  that  the  same  succession  of  replacements  of  one  construction 
by  another  which  has  sent  the  old  Rodman  cast-iron  gun  into  limbo  and  has 
already  sent  the  wrought-iron  built-up  gun  after  it  will  in  time  dispose  of  the 
steel  built-up  gun  in  precisely  the  same  manner ;  but  there  is  at  the  same  time 
no  doubt  to  my  mind  that  for  heavy  ordnance,  such  as  we  are  now  accustomed 
to  see  adopted  for  the  more  important  coast  defenses  and  heavier  iron-clads  of 
the  day,  the  steel  huilt-up  forged  gun  represents  the  best  existing  system.  I 
agree  heartily  with  the  writer  of  the  paper,  as  must  every  good  citizen,  that  the 
industry  of  making  such  guns  should  be  fostered  in  this  country,  even  at  the 
expense  of  large  sacrifices  by  our  taxpayers.  This  is  a  matter  of  simple  self- 
protection  and  insurance.  One  of  the  great  dangers  constantly  threatening  our 
nation  is  that  which  comes  of  its  persistent  and  criminal  neglect  to  take  the 
most  ordinary  of  precautions  in  self -protection  against  foreign  possible  enemies 
among  nations  which  have  no  such  commercial  interests  to  guarantee  a  peaceful 
disposition  as  has,  for  example,  our  own  mother  country.  Once  we  have  the 
material  required  for  the  manufacture  of  good  guns,  and  establishments  capable 
of  turning  them  out  in  large  numbers,  we  have  improved  our  chances  of  preserv- 
ing the  peace  and  of  securing  respectful  consideration  of  our  rights  and  interests 
on  the  part  of  other  nations  enormously.  It  will  probably  be  admitted  on  all 
sides  that  the  United  States  Government  is  not  called  upon,  by  motives  of 
either  statecraft,  business,  or  simple,  wise  provision  of  possible  disputes  with 
other  nations,  to  do  more  than  to  institute  effective  means  of  self-defense ;  but 
it  is  probably  quite  as  generally  recognized  as  the  part  of  wisdom  to  make  our 
defenses  against  any  possible  foreign  aggression  as  absolutely  safe  as  our  knowl- 
edge, skill,  and  wealth  will  allow.  In  this,  as  in  most  matters  of  business,  the 
best  preparation  and  the  best  material  are  the  cheapest  in  the  end. 

Finally,  in  regard  to  the  Treadwell  and  other  systems  of  wire-wound  guns, 
it  may  be  said  that,  while  their  theory  is  unquestionably  in  many  respects  cor- 
rect and  somewhat  promising,  we  have,  so  far  as  I  am  aware,  no  evidence  indi- 
cating that  the  universally  recognized  practical  difficulties  to  be  overcome  in 
their  manufacture  and  use  are  likely  soon  to  be  satisfactorily  disposed  of.  As 
to  steel-cast  guns,  I  have  no  doubt  that  they  will  come  into  use,  but  it  will  be 
first  necessary  to  insure  that  they  do  not  represent  the  conditions  enunciated  by 
Captain  Birnie,  and  their  advocates  must  be  able  to  do  more  than  assert  that 
"  steel  in  a  relatively  weak  condition  is  abundantly  strong  for  the  work  required 
of  a  gun."  We — for,  with  this  qualification,  I  am  one  of  those  advocates — must 
first  find  means  of  securing  greater  resilience  of  mass  per  pound  weight  in 
that  gun  than  in  the  built-up  gun.     I  think  that  in  time  the  Whitworth  and 


GUN   MAKING  IN   THE   UNITED    STATES.  131 

Dean,  or  other  processes  or  combination  of  processes,  will  bring  about  this  desir- 
able state  of  the  art  of  great  gun  manufacture.  With  regard  to  the  metal,  it 
may  be  said  that  no  form  of  iron,  steel,  or  other  metal  is  "  strong  enough  "  and 
tough  enough  for  ordnance  if  we  can,  by  any  possibility,  find  another  which  is, 
in  the  mass,  stronger,  whatever  the  material  and  however  put  together.  A 
nation  on  the  defensive  may  not  need  many  guns ;  but  that  is  all  the  better 
reason  for  insisting  that  those  which  are  supplied  shall  be  the  representatives 
of  the  highest  skill  the  world  can  offer. 

It  is  a  singular  fact  that  while  nearly  every  great  inventor  in  this  field  is 
an  American,  trained  in  the  school  of  the  American  mechanic  and  encouraged 
by  the  grandly  successful  patent  system  of  this  country,  they  are  all,  invariably, 
compelled  to  seek  the  reward  of  their  industry,  skill,  ingenuity,  and  persistence 
among  the  nations  of  Europe  and  among  peoples  who  have  never  known  the 
advantages  of  this  form  of  protection  of  home  industry.  It  is  to  be  hoped  by 
every  good  citizen  that  after  a  time,  when  the  National  Legislature  shall  have 
awakened  from  its  Rip  Van  Winkle  slumber — if  meantime  some  powerful  foe 
has  not  demolished  our  mock  defenses  and,  like  Prussia  after  the  last  Franco- 
German  war,  inflicted  a  fine  that  shall  cripple  us  completely — our  inventors  and 
our  long-suffering  army  and  navy  officers  may  see  some  slight  attempt  made 
to  at  once  secure  for  the  country  an  insurance  against  such  dangers  and  a 
reward  for  their  patriotic  and  earnest  endeavors. 

James  E.  Howard,  Esq.,  Watertown  Arsenal. 

In  the  construction  of  modern  forged  steel  guns,  a  superior  metal  is  employed 
which  combines  high  elastic  properties  and  tensile  strength  with  a  very  con- 
siderable amount  of  toughness,  together  with  homogeneity  and  soimdness  of 
structure. 

This  gun  steel  occupies  an  intermediate  position  in  degree  of  hardness  between 
the  mild  structural  steels  and  the  higher  grades  of  spring  and  tool  steels.  Very 
elaborate  tests  of  quality  here  have  been  made,  which  serve  to  establish  its  relia- 
bility, and  the  thorough  method  of  inspection  employed  identifies  and  secures  the 
acceptance  of  metal  of  the  high  standard  of  excellence  which  has  been  attained. 
The  requirements  of  a  gun  metal  are  necessarily  severe ;  a  certain  strength  it 
must  have,  and  it  should  have  ample  strength  to  compete  on  even  terms  with 
any  weapons  which  may  be  encountered ;  in  other  words,  only  the  best  metal 
for  the  purpose  should  be  employed. 

The  metal  adopted  in  the  construction  of  modern  forged-steel  guns  seems  to 
possess  in  the  aggregate  the  greatest  number  of  desirable  qualities  now  attain- 
able. 

To  review  briefly  the  physical  properties,  mild  steels  approach  in  qualities  the 
best  grades  of  refined  wrought  iron ;  they  are  low  in  elastic  limit  and  tensile 
strength,  but  possess  great  toughness,  as  shown  by  the  elongation  of  the  metal 
before  rupture  and  by  its  contraction  in  area  at  the  place  of  rupture. 

Manipulation,  cold,  will  elevate  the  elastic  limit  and  tensile  strength,  but  at 
the  same  time  detracts  from  its  toughness. 

This  method  of  increasing  its  resistance  is  limited  in  its  application  prac- 
tically to  a  number  of  simpler  forms  into  which  the  metal  may  be  put. 

Mild  steel  is  slightly  affected,  comparatively,  by  surface  defects  of  limited 
extent,  such  as  indentations  from  hammer  blows  or  cutting  tools  and  the  like, 
the  relative  influence  of  such  defects  increasing  in  serious  importance  with  the 
increase  in  hardness  of  the  steel. 

The  relative  deleterious  effects  of  interior  defects  of  structure,  such  as  may 
exist,  in  different  grades  of  metal  are  very  difficult  of  ascertainment,  such  infor- 
mation coming  incidentally  with  a   large   experience  in  working  the  several 


132  GUN    MAKING   IN   THE    UNITED   STATES. 

metals  under  a  variety  of  circumstances.  Tliis  much  may  be  said,  however,  that 
instances  have  been  met  wherein  the  very  softest  steels  have  suddenly  fractured 
with  a  display  of  brittleness  unsurpassed  by  the  higher  grades  of  steel.  No 
steel  which  has  been  impi'operly  treated  seems  to  be  exempt  from  this  behavior, 
and  investigations  have  shown  pretty  clearly  what  is  proper  and  what  is 
improper  treatment.  These  remarks  have  reference  to  the  mechanical  treat- 
ment of  steel  apart  from  questions  of  chemical  composition.  As  we  advance  to 
the  higher  grades  of  metal,  higher  elastic  limits  and  tensile  strength  are  found 
with  less  elongation  and  contraction  of  area. 

Gun  steel  is  characterized  by  its  high  elastic  limit  and  tensile  strength,  com- 
bined with  an  extraordinary  degree  of  toughness. 

The  modulus  of  elasticity  has  been  found  to  remain  substantially  the  same  in 
steels  extending  over  a  wide  range  in  chemical  composition  and  not  to  be  sen- 
sibly different  in  tempered  and  annealed  bars,  hot  rolled  and  cold  rolled  bars. 

A  reduction  in  the  modulus  of  elasticity  follows  overstraining,  but  this  has 
been  found  transitory  in  all  specimens  thus  far  examined. 

Under  higher  temperatures  there  is  a  reduction  in  the  modulus  of  elasticity, 
the  reduction  going  on  as  the  temperature  increases,  the  practical  effect  of  which 
in  a  gun  would  seem  to  be  the  introduction  of  the  principle  of  "  varying  elas- 
ticity "  while  the  gun  had  a  temperature  at  the  bore  higher  than  at  the  exterior. 

While  the  elastic  limit  is  lower  than  at  atmospheric  temperatures,  yet  the  ten- 
sile strength,  after  showing  a  slight  reduction  in  the  vicinity  of  2.50°  F.,  in- 
creases from  this  temperature  or  thereabouts  until  at  500°  to  600°  F.  the 
increase  in  strength  amounts  to  from  15  to  20  per  cent  of  its  strength  cold. 

It  has  been  further  observed  that  bars  which  have  been  strained  while  at 
these  higher  temperatui'es  by  loads  in  excess  of  the  strength  cold  were  not 
thereby  weakened  when  afterwards  tested  to  rupture  at  atmospheric  tempera- 
tures, but,  on  the  other  hand,  were  found  to  retain  the  strength  due  to  the  high 
temperatures  at  which  they  had  previously  been  strained. 

The  coefl3cient  of  expansion  by  heat  appears  to  be  influenced  by  the  chemical 
composition  of  the  steel. 

A  series  of  observations  made  on  steel  bars,  ranging  in  carbon  from  0.10  per 
cent  to  1  per  cent,  the  other  elements  present  not  varying  in  regular  succession, 
showed  a  progressive  reduction  in  the  coefficient  of  expansion  as  the  percentage 
of  carbon  increased. 

The  mild  steels  showing  about  the  same  rate  of  expansion  as  wrought  iron, 
the  hard  steels  not  reaching  quite  so  low  a  coefficient  as  that  of  cast  iron,  but 
cast  iron  contains  a  much  larger  amount  of  carbon  than  the  highest  steels  ex- 
perimented upon. 

Internal  strains  may  exist  in  steels  and  other  metals.  They  are  an  advantage 
in  guns  when  disposed  according  to  certain  laws  governing  the  resistance  of 
cylinders. 

When  they  exist  locally  and  of  great  intensity,  they  become  correspondingly 
disadvantageous  and  may  cause  unexpected  fracture  of  the  metal. 

The  intensity  of  such  strains  is  limited  by  the  elastic  limit  of  the  metal,  and 
treatment  that  elevates  the  elastic  limit  thereby  increases  the  capacity  for 
receiving  internal  strains. 

The  introduction  of  internal  strains  in  well-annealed  metal  depends  upon,  at 
least  in  a  measure,  changes  in  density,  and  to  effect  a  permanent  change  of 
density  by  cold  treatment  necessitates  a  permanent  set  or  flow  of  the  metal, 
from  which  it  follows  that  the  higher  the  elastic  limit  the  more  difficult  will  it 
be  to  introduce  internal  strains  by  the  application  of  external  stresses. 

The  advantages  which  high  grades  of  steel  possess  in  the  direction  just 
referred  to  are  not  known  to  be  offset  by  counter  disadvantages  resulting  from 
moderate  changes  in  temperature. 


GUN    MAKING   IN    THE   UNITED    STATES.  133 

Commander  R.  D.  Evans,  U.  8.  Nary. 

One  can  only  speak  In  terms  of  the  highest  praise  of  this  excellent  article,  and 
had  I  the  time  to  do  so  I  would  like  to  place  myself  properly  on  record  with 
reference  to  the  matter  of  "  steel-cast "  guns.  I  have  for  many  years  advocated 
the  steel-cast  gun  and  firmly  believe  that  it  will  prove  the  gun  of  the  future, 
but,  at  the  same  time.  I  would  not  in  any  Avay  interfere  with  or  defer  the  mak- 
ing of  built-up  guns,  which  we  have  reason  to  know  are  good.  There  seems  to 
me  to  be  ample  room  for  both  systems,  and  I  hope  the  great  industry  of  steel 
casting  may  have  proper  encouragement. 

Capt.  .John  G.  Butlee,  Ordnance  Department. 

As  it  is  perhaps  true  that,  after  Mr.  William  P.  Hunt.  I  am  chiefly  responsible 
for  the  existence  of  the  12-inch  breech-loading  gun  at  Sandy  Hook,  it  may  follow 
that  I  am  qualified  to  speak  upon  that  part  of  Captain  Birnie's  able  paper 
devoted  to  cast-iron  guns.  But  since  the  practical  attainment  of  my  own  wishes 
in  the  successful  efforts  of  Mr.  Hunt  before  the  Logan  committee,  it  has  been 
rather  as  "  a  looker-on  in  Vienna  "  that  I  have  interested  myself  in  the  gun 
question,  and  I  am  somewhat  averse  to  entering  the  arena  of  discussion.  Never- 
theless, as  I  think  that  the  prejudices  of  the  author  of  "  Gun-Making "  have 
stood  a  little  in  his  way  as  a  fair  historian,  I  will  undertake  to  correct  two  or 
three  of  his  statements,  although  I  fear  that  it  will  be  impossible  to  confine  my 
remarks  within  the  limits  which  you  find  it  necessary  to  assign  to  the  discussion. 

Captain  Birnie  is  certainly  the  first  ordnance  officer  who  ever  found  anything 
to  admire  in  the  report  of  the  Select  Committee  on  Ordnance,  1869.  This  com- 
mittee announced  a  number  of  conclusions.  Among  them  was  one  condemning 
the  Rodman,  Dahlgren,  and  Parrott  "  systems  "  as  applied  to  rifles,  and  this  he 
considers  so  powerful  a  backing  to  his  argument  that  he  exults  over  it  more  than 
once,  and  overlooks  another  conclusion  of  the  committee  condemning  all  Euro- 
pean "  systems  "  as  showing  "  no  exemption  from  the  rule  of  failure,"  and  dis- 
countenancing their  trial  in  this  country.  The  committee  in  no  place  condemned 
cast  iron  or  cast-iron  guns  per  se,  as  Captain  Birnie  seems  to  think,  but  its 
report  was  made  to  do  duty  last  winter  in  parading  before  Senators  and  Repre- 
sentatives lists  of  Rodman,  Dahlgren,  and  Parrott  rifles  which  had  failed,  care- 
fully suppressing  the  flne  records  of  many  of  these  guns  and  making  no  men- 
tion of  well-known  causes  of  failure  in  others. 

The  argument  for  the  fair  trial  of  strong  cast  iron  as  a  material  for  heavy 
rifles  was  largely  based  upon  the  admirable  performance  of  many  cast-iron  guns 
and  the  brutal  treatment,  by  vicious  systems  of  projectiles  and  rifling,  which 
seemed  to  justify  the  failure  of  others.  It  has,  perhaps,  "  suited  the  interests  " 
of  the  friends  of  cast  iron  to  call  attention  to  its  record  just  as  it  now  appears 
to  "  suit  the  interests  "  of  Captain  Birnie  to  discredit  that  record  and  place  his 
individual  opinion  against  the  judgment  of  men  who  formed  theirs  at  the  proof 
butts.  Many  ofiicers  of  distinction  witnessed  these  experiments  more  than 
twenty  years  ago,  while  the  author  of  "  Gun-Making  "  was  employed  elsewhere. 
The  enormous  strains  to  which  the  guns  of  that  day  were  subjected  were  not 
theoretical ;  the  facts  were  there  for  observation.  The  then  Chief  of  Ordnance, 
General  Dyer,  fifteen  years  ago  ordered  a  discontinuance  of  his  own  soft-base 
projectile  and  directed  the  use  of  the  Butler  projectile  in  experiments  with 
powder  then  going  on.  Krupp  shortly  after  abandoned  his  lead-jacketed  pro- 
jectiles, eccentric  chamber,  and  narrowing  grooves — a  system  which  had  hitherto 
restricted  his  guns  to  the  use  of  comparatively  light  charges — and  adopted  the 
copper-banded  projectile — and  lo !  the  result  at  Meppen  in  1878.  The  English 
about   the  same  time   abandoned  their   studded  projectiles   and   took   up   the 


134  GUN    MAKING   IN   THE    UNITED   STATES. 

expanding  system  for  their  muzzle-loaders,  and  it  is  a  perfectly  noteworthy  fact 
that  from  the  adoption  of  reliable  muzzle-loading  and  breech-loading  projectiles 
it  has  all  been  smooth  sailing  for  the  development  of  guns  and  powders,  the 
pressures  having  been  brought  practically  under  control. 

Captain  Birnie  is  not  more  fortunate,  I  think,  in  ascribing  the  heavy  pressures 
formerly  recorded  to  "  defective  means  of  measurement "  or  inexperience  with 
the  Rodman  gauge.  The  exterior  gauge  was  rarely  used ;  the  interior  gauge 
had  been  used  for  years;  the  same  officer  (Colonel  Baylor),  who  used  it  at  Fort 
Monroe,  afterwards  used  it  for  years  at  Sandy  Hook,  and  his  experience  with 
this  gauge  and  various  ballistic  instruments  was  larger  than  that  of  any  officer 
in  this  or  perhaps  any  service.  Again,  the  very  same  employee — Hickey — who 
had  prepared  the  gauge  for  years  at  Fort  Monroe,  both  for  Army  and  Navy 
experiments,  was  afterwards  employed  at  Sandy  Hook  in  setting  up  the  same 
instrument,  and  is  probably  thus  employed  at  the  present  time.  In  regard  to 
the  few  Indications  of  pressure  supposed  to  exceed  that  due  to  the  explosion 
of  gunpowder  when  confined  within  its  owm  volume,  it  is  possible  that  when 
this  high  limit  has  been  approximated  in  the  gun  intense  local  action  has  inter- 
fered with  the  normal  action  of  the  gauge. 

I  think  I  must  mention  one  instance  of  Captain  Birnie's  inconsistency  in  his 
opinion  that  the  "  true  reason  "  for  the  bursting  of  cast-iron  guns  was  "  the 
frailty  of  the  guns  themselves,"  and  in  his  emphatic  "  opinion  "  that  bad  pro- 
jectiles and  rifling  had  little  to  do  with  it.  I  refer  to  his  own  citation  of  experi- 
ments at  Nut  Island  with  15-inch  guns  rifled  with  two  grooves.  He  says :  "As 
an  illustration  of  what  cast-iron  rifles  "  will  stand  when  badly  treated  (thereby 
implying  that  they  had  not  heretofore  been  "  badly  treated  "•)  we  may  extract 
the  four  guns  of  this  class '^  (conveying  the  impression  that  they  were  "cast- 
iron  rifles"  in  an  ordinary  sense)  which  were  included  in  Wiard's  somewhat 
notorious  experiments  at  Nut  Island  in  1873-1875,"  and  he  then  cites  these 
so-called  "  rifles  "  which  burst  at  the  nineteenth,  second,  and  seventh  rounds, 
respectively,  with  charges  of  from  100  to  140  pounds  of  powder.  Now,  if  the 
Wiard  projectiles  did  not  burst  these  guns,  how  is  their  failure  at  the  very  outset 
of  the  firing  to  be  accounted  for,  in  view  of  what  Captain  Birnie  calls  elsewhere 
"  the  present  efficiency  of  the  15-inch  guns  with  increased  charges?  "  If,  on  the 
other  hand,  the  projectiles  did  burst  the  guns  (if  I  may  venture  upon  so  rash  an 
hypothesis)  his  citation  is  inconsistent  with  the  position  which  he  has  chosen  to 
take  on  the  question.  Even  his  qualifying  admission  that  "  The  Wiard  rifles  are 
generally  admitted  to  have  been  destroyed  by  excessive  charges  and  bad  projec- 
tiles "  he  can  not  bear  to  let  stand,  and  therefore  adds :  "  Yet  the  charges  he  used 
bear  no  comparison  with  those  now  required  to  be  used  in  steel  guns."  Very  true, 
neither  in  quantity,  which  he  refers  to,  nor  in  quality,  which  he  does  not. 
Nor  do  they  bear  comparison  with  the  265-pound  charges  of  the  12-inch  cast- 
iron  rifle;  but  how  much  over  100  pounds  of  powder,  bottled  up  in  the  bore,  or 
operating  behind  a  projectile  which  acts  as  a  wedge,  does  Captain  Birnie  con- 
sider necessary  to  burst  a  gun? 

The  concluding  paragraph  of  the  chapter  on  the  cast-iron  rifle  touches  me  per- 
sonally, and  not  very  generously,  and  as  the  statements  are  entirely  erroneous 
and  have  appeared  in  newspapers,  it  is  perhaps  as  well  to  at  least  notice  them. 
The  paragraph  covers  a  considerable  portion  of  the  history  of  the  case,  and  I 
beg  to  quote  it  entire : 

"  The  ability  which  the  officers  of  the  Ordnance  Department  have  shown  in 
designing  so  powerful  a  cast-iron  rifle  as  the  one  lately  proved  is  an  earnest  of 
their  desire  and  capacity  to  carry  out  whatever  Congress  may  direct.    Had  the 

«  Italics  marked  are  mine. 


GUN    MAKING   IN    THE    UNITED    STATES.  135 

12-lnch  cast-iron  rifle  been  made  after  a  design  presented  to  the  Logan  com- 
mittee, that  was,  to  fire  150  poimds  of  powder  with  700-pound  shot,  and  give  a 
muzzle  energy  of  but  10,000  foot-tons,  instead  of  the  17,000  foot-tons  procured  in 
the  design  actually  used — but  little  interest  would  attach  to  a  discussion  of  its 
merits  here  or  elsewhere." 

Briefly,  and  perhaps  flatly,  I  will  say  that  I  designed  this  and  other  of  Mr. 
Hunt's  guns  which  were  before  the  committee,  and  that  the  design  has  been 
adhered  to  in  good  faith  by  the  Chief  of  Ordnance.  In  the  light  of  many 
months'  later  experience  a  few  changes  were  made  by  the  Ordnance  Oflice.  with 
this  difference  in  our  judgment,  that,  whereas,  the  only  change  of  moment 
(enlarging  the  chamber),  which  was  made  before  initial  proof,  I  would  have 
made  later  on  and  did  anticipate  and  provide  for  three  years  previously. 

I  first  urged  for  the  trial  of  a  12rinch  cast-iron  rifle  about  fifteen  years  ago, 
before  the  Heavy  Gun  Board  of  1872,  and  on  subsequent  occasions  have  contin- 
ued to  argue  that  such  a  gun  should  be  tested  under  the  modern  conditions  of 
improved  powder  and  projectiles.  In  1881  my  friend  Mr.  Hunt  and  myself, 
being  nearly  of  one  mind  on  the  subject,  I  assisted  him  in  the  preparation  of  his 
case  for  presentation  to  the  Getty  Board  upon  two  conditions,  namely :  That 
he  should  make  no  acknowledgement  of  my  services  (for  one  reason,  that  I 
did  not  wish  to  appear  before  any  committees),  and  that  I  should  receive  no 
pecuniary  compensation  from  his  company.  He  urged  before  that  board  a 
12-inch  breech-loading  cast-iron  rifle  ("  D  ")  to  be  tested  in  comparison  with  the 
four  12-inch  B.  L.  rifles  then  under  contract  for  the  Government,  but  subse- 
quently abandoned.  Following  this  design  ("D")  were  two  other  ("E")  and 
("F")  exactly  similar  in  outline  and  dimensions  to  the  cast-iron  rifle,  but 
differing  from  each  other  in  that  one  was  lined  with  a  short  steel  tube  and  the 
other  was  hooped  with  steel.  This  Gun  Board  of  1881-82— with  the  exception 
of  the  two  ordnance  officers — became  badly  afflicted  with  the  steel-wire  craze, 
and  its  report  was  not  fully  concurred  in.  The  Logan  committee  was  appointed, 
and  before  it  Mr.  Hunt  and  others  laid  their  plans.  The  cast-iron  rifles  designs 
"  D  "  and  "  F  "  were  to  be  cast  breech  up,  for  reasons  given ;  they  had  the 
Hodman  contour  as  far  as  the  breech,  a  slight  portion  of  which  only  was 
cylindrical  so  as  to  conform  to  that  outline  which  was  most  economical  and 
convenient  for  the  hooped  gun  "  F."  A  few  inches  of  taper  on  the  base  of  design 
"  D  "■ — a  question  of  taste,  not  utility — gives  the  curve  of  the  gun  at  Sandy 
T-Iook.  In  all  designs  for  cast-iron  guns,  whether  entirely  of  that  metal  or  steel- 
hooped,  I  introduced  the  feature  of  a  steel  sleeve,  or  housing,  for  the  slotted 
screw  breechblock,  so  as  to  avoid  cutting  away  half  of  the  cast-iron  thread,  a 
feature  which  has  been  retained.  The  character  of  the  pitch  was  that  which 
I  had  urged  for  many  years,  now  widely  adopted,  i.  e.,  an  increasing  pitch  in 
which  the  angle  at  the  breech  bears  a  reasonable  relation  to  that  at  the  muzzle. 
I  provided  for  fewer  grooves  and  an  expanding  projectile,  because  at  the  time 
it  was  thought  easier  on  the  gun.  The  character  of  the  rifling  was  otherwise 
practically  retained,  the  angle  being  slightly  changed,  but  as  3  or  4  feet  were 
added  to  the  muzzle — which  Mr.  Hunt  would  probably  have  added  without  sug- 
gestion— I  suppose  that  this  little  end  of  the  gun  was  not  considered  Mr. 
Hunt's  property,  and  so  in  it  there  is  a  sudden  return  to  the  old  love  and  the 
pitch  made  uniform  for  about  3  feet. 

The  test  of  these  guns  was  especially  urged  (pp.  viii,  79,  80,  Hunt)  as  serving 
to  determine :  1.  Whether  a  serviceable  heavy  breech-loading  rifle  could  be  made 
of  cast  iron  pure  and  simple.  2.  The  extent  to  which  steel  as  an  auxiliary 
might  be  beneficial.  3.  Whether  it  would  be  better  to  apply  the  steel  inside  as 
a  tube  or  outside  as  a  jacket — the  latter  plan  being  the  more  expensive.  The 
report  of  the  Logan  committee  was  concurred  in  by  Congress,  and  among  the 


136  GUN    MAKING    IN   THE    UNITED   STATES. 

guns  appropriated  for  were  two  cast-iron  12-inch  breecb-Ioading  rifles  and  one 
cast-iron  rifle  banded  or  hooped  with  steel.  As  these  guns  bad  been  urged.  I 
believe,  by  Mr.  Hunt  alone — the  ordnance  office  favoring  only  the  all-steel  and 
the  French  systems — it  was  considered  that  the  three  guns  thus  designated 
meant  Mr.  Hunt's,  and  as  it  was  thought  that  the  committee  had  intended  to 
add  the  words  "  one  to  be  lined  with  a  steel  tube."  after  the  words  "  two  12-inch 
cast-iron  rifles,"  etc.,  Mr.  Hunt  suggested  and  obtained  authority  to  put  a  steel 
tube  in  one  of  them.,  I  have  seen  this  circumstance  i*eferred  to  as  though  it 
marked  some  lack  of  confidence  on  Mr.  Hunt's  part  in  the  cast-iron  gun,  and 
therefore  deem  it  pi'oper  to  say  that  he  made  the  request  at  my  written  solicita- 
tion. The  argument  for  the  test  of  the  series  of  guns  ("'D,"  cast-iron;  "  E," 
cast-iron  lined;  "  F,"  cast-iron  banded)  was  logically  sound;  my  own  argu- 
ments on  professional  grounds  fitted  into  his  from  a  manufacturer's  standpoint ; 
we  had  worked  hard  to  get  the  guns  and  succeeded.  I  believe  that  on  bis  own 
account  Mr.  Hunt  would  have  preferred  the  two  cast-iron  guns  intact,  but  he 
cheerfully  made  the  concession  to  me. 

This  gun  was  not  originally  designed  to  fire  "  but  150  pounds  of  powder." 
Mr.  Hunt  was  willing  to  guarantee  such  a  charge,  or  10,000  foot-tons  energy, 
and  this  being  at  the  time  well  up  to  the  standard  for  service  guns  of  like 
caliber  abroad,  he  argued  that  the  proof  of  the  guu  should  be  commenced  with 
that  chai'ge.  But  the  identical  figures  (17.000  foot-tons)  which  Captain  Birnie 
now  gives  great  credit  for  in  another  quarter  was  provided  for  as  a  contingent 
proof  for  this  gun  as  far  back  as  July,  1881  (p.  33,  Hunt).  True,  the  charge 
of  225  pounds  of  powder  then  provided  for  might  not  have  quite  accomplished 
this  result,  but  it  was  never  pretended  to  accurately  determine  the  chambers  of 
any  of  the  guns  until  working  drawings  were  required,  and  it  was  a  year  or 
two  after  the  appropriation  for  this  rifie,  and  three  years  after  the  charge 
of  225  pounds  was  suggested  to  the  Getty  Board,  that  the  dimensions  of  the 
chamber  were  finally  fixed.  This  hardly  constituted  a  "  design,"  and  it  will 
also  be  admitted,  perhaps,  that  adding  a  little  to  the  muzzle  of  a  gun  originating 
with  and  produced  Tnj  others,  or  making  it  exactly  of  i-inch  greater  semi- 
diameter  at  the  breech,  or  adopting  a  slight  change,  or,  in  fact,  any  change  of 
rifling,  is  not  designing  a  gun  in  any  rational  sense.  Furthermore.  I  claim  that 
these  changes  were  not  dictated  by  the  best  judgment.  Mr.  Hunt's  programme 
was  to  begin  proof  with  charges  giving,  say,  10.000  foot-tons  energy,  which,  if 
sustained  up  to  a  certain  number  of  rounds  (100  rounds  were  guaranteed), 
would  by  our  agreement,  which  appeared  to  satisfy  the  committee,  justify  the 
construction  of  this  cheap  gun.  After  this  the  chamber  would  have  been 
reamed  up  to  hold  the  225  pounds  specified,  and  after  further  proof  we  could 
ultimately  reach  270  pounds,  and  perhaps  300  pounds  of  powder  and  800-pound 
shot,  with  which  charge  the  proof  could  have  been  continued.  This  would  have 
left  the  chamber  in  perfect  condition  for  the  heavier  charges.  It  was  not  a 
well-ordered  experiment  to  jump  at  once  for  the  maximum  effect.  What  was 
wanted  was  the  true  measure  of  the  gun's  strength  or  weakness,  and  this  would 
not  give  it ;  our  programme  would  have  developed  the  same  power,  but  I  think 
more  wisely,  and  the  proof  of  the  gun  would  have  been  further  and  more 
intelligently  advanced.  I  think,  therefore,  that  Captain  Birnie  is  mistaken  in 
claiming  for  "  the  oflicers  of  the  Ordnance  Department " — whether  this  means 
himself  or  coadjutors — any  credit  for  "  designing  "  what  he  is  pleased  to  call 
"  so  powerful  a  cast-iron  rifie  as  the  one  lately  proved."  One  would  suppose 
that  he  would  hesitate  before  putting  himself  or  friends  into  the  peculiar 
position  of  first  energetically  opposing  the  construction  of  a  gun  and  afterwards 
claiming  credit  for  all  there  was  in  it.  Mr.  Hunt  as  the  manufacturer,  and  I 
as  the  designer,  and  both  of  us  as  the  originators  of  the  12-inch  breech-loading 


GUN   MAKING   IN    THE   UNITED    STATES.  137* 

cast-iron  rifle,  have  to  tliank  tlie  Messrs.  Du  Pont  for  an  excellent  powder,  and 
there  our  obligation  ends. 

Another  important  contingency  was  provided  for  in  connection  with  heavy 
cast-iron  guns.  The  admirable  conservation  of  the  bores  of  cast-iron  rifles  had 
been  observed,  but  with  improvement  in  gunpowders  the  tendency  would  be  to 
increase  of  charge  and  weight  of  shot,  and  under  the  longer  sustained  heat  and 
action  of  the  powder  gases  it  was  possible  that  the  surface  of  the  chamber  and 
of  its  junction  with  the  bore  might  need  protection.  I  therefore  revived  an 
idea  which  occurred  to  me  several  years  previously  at  Fort  Monroe,  upon  exam- 
ining the  bottom  of  the  bore  of  a  gun  which  had  been  fired  many  times,  and 
suggested — as  referred  to  in  IMr.  Hunt's  letters  to  the  Getty  Board,  page  49 — 
a  chamber  lining  of  thin  steel  or  copper,  which  would  be  removable  at  pleasure. 
I  think  the  chamber  of  the  12-inch  gun  should  now  be  reamed  up  and  this  thin 
steel-lining  tube  inserted.  It  has  nothing  to  do  with  the  strength  of  the  struc- 
ture and  is  now  thought  advisable,  I  believe,  in  heavy  steel  guns.  Had  the 
chamber  of  this  gun  been  made  smaller  in  the  first  place  a  beautiful  new  sur- 
face could  have  been  presented  for  every  one  or  two  hundred  rounds  of 
increasing  proof  charges. 

For  the  rest,  although  I  believe  that  the  character  of  many  of  our  harbors 
and  the  enormous  extent  of  our  coast,  combined  with  our  grievous  necessities, 
should  long  since  have  prompted  the  definite  settlement  of  the  question  how 
far  cast  iron  may  be  available  for  heavy  coast  guns,  yet  I  am  in  hearty  accord 
with  all  efforts  looking  to  the  development  of  gun-steel  industries  and  to  the 
highest  type  of  the  steel  gun.  Captain  Birnie  presents  one  of  the  ablest  argu- 
ments in  this  direction  that  has  come  to  my  notice,  and  although  much  that  he 
says  is  already  familiar  to  ordnance  officers — in  part  by  his  own  excellent  pro- 
fessional work — yet  I  have  read  his  paper  with  fresh  interest  and  profit.  Nor 
is  any  apology  necessary,  in  my  opinion,  for  past  failures ;  the  Government  is 
rich  enough  to  support  experiment.  The  material  is  here,  and  if  it  needs 
improvement,  the  metal  workers  are  here  to  accomplish  it.  The  mechanical 
part  of  the  problem  is  small,  the  "  designing  "  is  still  less ;  the  metallurgist  will 
create  the  "  gun  of  the  future."  But  I  believe  that  a  "  high-power  gun  "  should 
mean  a  high-pressure  gun  (the  variety  of  our  powders  is  becoming  too  compli- 
cated). We  do  not  want  a  tube  as  long  as  the  moral  law,  begging  for  easy 
treatment  by  the  powder,  but  a  shorter,  more  compact,  and  more  convenient 
weapon.  "  High-power  ammunition  "  would  be  much  more  appropriate  expres- 
sion at  the  present  time,  for  to  the  powder  manufacturer  is  really  due  most 
of  the  credit  now  so  complacently  absorbed  by  the  gun  exponents.  Rodman  is 
occasionally  named  as  a  man  well  enough  in  his  day,  but  I  rarely  see  the  name 
of  Du  Pont  mentioned. 

Lieut.  William  Crozier.  Ordnance  Department. 

Progress  is  the  movement  in  the  mechanical  arts,  traveling  the  parallel  roads 
of  increased  economy  and  increased  efficiency. 

A  fixed  belief  in  the  excellence  and  serviceability  of  a  type  of  mechanical  con- 
struction, while  supplying  the  confidence  necessary  for  engaging  in  its  exten- 
sive reproduction,  is  not  incompatible  with  investigation  as  to  the  lines  of 
possible  improvement. 

The  lecturer  has  stated  his  appreciation  of  this  fact,  and  while  urging  the 
manufacture  of  the  built-up  forged-steel  gun,  a  satisfactory  and  now  undoubt- 
edly the  best  type,  has  had  a  not  discouraging  word  for  the  two  most  prominent 
attempted  improvements  under  trial,  viz,  the  steel-cast  gun  and  the  wire  gun. 
With  reference  to  the  former  he  has  indicated  very  clearly  the  requirements, 
the   difficulty   of   attaining  them,   and   the   results   of   falling   short   of   them. 


138  GUN    MAKING   IN   THE    UNITED   STATES. 

I  will  call  attention  only  to  the  fact  that  the  progress  attempted  to  be  realized 
in  this  effort  is  in  the  direction  of  economy  only,  the  less  important  of  the 
two  roads ;  and  that,  as  far  as  efficiency  is  concerned,  its  advocates,  while 
claiming  in  general  terms  that  it  will  be  as  great  as  in  the  built-up  guns,  prac- 
tically concede  in  their  specifications  that  it  will  be  less ;  making,  therefore,  a 
step  backward  in  this  direction. 

The  almost  universal  law  of  progress  is  that  it  is  from  the  simj^le  to  the  com- 
plex ;  improvement  in  material  and  combination  overcoming  the  disadvantage 
of  complexity,  and  increased  expense  being  more  than  compensated  for  by 
increased  efficiency.  A  return  to  simplicity  for  simplicity's  sake  at  a  sacrifice 
of  efficiency  is  rare  indeed  in  the  arts. 

I  will  now  try  to  indicate  briefly  what  constitutes  the  promise  of  the  wire 
gun,  what  are  the  difficulties  in  the  way  of  the  fulfillment  of  the  promise,  and 
what  the  probable  lines  along  which  the  difficulties  may  be  overcome.  The 
main  object  sought  to  be  attained  in  wire  guns  is  great  tangential  resistance 
without  corresponding  sacrifice  in  other  directions.  The  desirability  of  this 
object  may  be  explained  as  follows : 

MM.  Sebert  and  Hugoniot  have  established  for  the  pressure  on  the  base  of 
the  projectile  the  formula 

W* 


P  =  P„ 


W  + 


in  which  Pq  is  the  pressure  at  the  breech,  AA^  is  the  weight  of  the  projectile,  and 
C  that  of  the  charge.    The  energy  of  the  projectile  is 


Wv'^ 


'A^-=v^:P"'-- 


If  we  take  the  axis  of  the  piece  as  the  axis  of  abscissas  and  plat  the  pressure 
curve  the  expression  /Podx  will  represent  the  area  under  this  curve,  to  which 
area,  therefore,  the  energy  of  the  projectile  is  proportional. 

If  the  strength  of  the  gun  permitted  the  use  of  a  kind  of  powder  or  method 
of  forcing  for  the  projectile  (or  both)  such  that  the  combustion  of  the  charge 
should  be  completed  befox'e  the  movement  of  the  projectile  commenced,  the  pres- 
sure with  the  stated  charge  of  100  pounds  and  density  of  loading  .9,  would  rise 
at  once  to  33.6  tons  and  fall  off  to  4  tons  at  the  muzzle,  instead  of  rising  to 
16  tons  after  a  movement  of  one  and  one-half  calibers  and  falling  to  2.9  tons, 
as  indicated  in  the  plate  accompanying  the  lecturer's  paper.  The  area  under 
the  pressure  curve  would  be  increased  about  one-third,  which  represents  the 
proportion  of  gain.  But  with  sufficient  strength  we  are  not  limited  to  the  use 
of  a  charge  of  100  pounds  and  density  of  loading  .9.  There  can  be  put  into 
the  chamber  of  the  S-inch  breech-loading  steel  rifle  a  quantity  of  powder  suffi- 
cient to  give  a  density  of  loading  about  1.15.  with  which  charge  and  the  con- 
dition of  complete  combustion  before  movement  the  pressure  would  rise  to 
about  45  tons  and  drop  to  5.34  tons  at  the  muzzle,«  more  than  doubling  the 

*Etude  des  Effects  de  la  Poudre,  by  H.  Sebert,   Lieut.  Col.  de  I'art  de  la 
Marine  et  Hugoniot,  Capitaine  de  I'art  do  la  Marine, 
o  The  pressures  are  computed  by  the  formula  of  Messrs.  Noble  and  Abel. 


n  =  «(-^)' 


057 


in  which  Po  is  the  pressure  per  square  inch  and  v  is  the  ratio  of  the  volume 
occupied  by  a  weight  of  water  equaling  that  of  the  charge  to  the  volume  occu- 
pied by  the  products  of  combustion. 

Researches  on  Explosives  by  Captain  Noble  and  F.  A.  Abel,  No.  II. 


GUN"   MAKING   IN   THE   UNITED    STATES.  139 

area  under  the  pressure  curve.  Heuce  the  energy  imparted  to  the  projectile 
would  be  more  than  double  that  under  present  conditions.  The  weight  of  the 
projectile  remaining  the  same,  the  velocity  would  be  increased  to  one  and  one- 
half  times  the  present,  or  to  2,737  feet  per  second. 

The  gain  from  increased  strength  of  construction  is  apparent.  These  con- 
ditions can  probably  never  be  fully  attained  in  practice,  but  subdivision  of  the 
grains  and  the  law  that  the  rate  of  combustion  is  proportional  to  the  pressure, 
together  with  our  ability  to  increase  the  severity  of  the  forcing,  are  means 
by  which  we  can  reach  a  very  close  approximation  to  them.  That  severity  of 
forcing  increases  and  does  not  diminish.  As  has  been  stated,  the  energy  of  the 
projectile  is  not  only  apparent  from  theoretical  considerations,  but  has  been 
proved  by  experiments  made  with  that  object  by  Messrs.  Noble  and  Abel  and  by 
MM.  Sebert  and  Hugoniot. 

Other  considerations  than  that  of  tangential  resistance  of  course  enter,  such 
as  erosion,  limiting  the  useful  pressure.  I  am  only  endeavoring  to  indicate  the 
limit  toward  which  we  may  strive. 

The  difficulty  of  longitudinal  resistance  in  wire  guns  is  one  with  which  all 
are  familiar.  Various  methods  have  been  devised  for  overcoming  it.  They 
can  be  divided  into  three  general  classes — those  which  place  the  resisting  mem- 
ber within  the  wire  coil ;  those  which  place  it  without,  and  that  of  Doctor 
Woodbridge,  which  brazes  the  wire  coil  into  a  solid  mass. 

But  the  difficulties  of  attaining,  even  theoretically,  the  high  tangential 
resistance  claimed  by  most  of  its  advocates  for  the  wire  construction  is  not  so 
generally  understood.  Misapprehension  upon  this  point  has  been  fostered  by 
the  assumption  of  unattained  and  unattainable  values  for  the  physical  con- 
stants in  cast  iron  and  steel '^  and  by  their  declining  to  be  governed  by  the 
rule,  so  strictly  observed  by  the  designers  of  built-up  guns,  that  no  part  of 
the  structure  shall  be  strained  beyond  the  elastic  limit  of  its  material,  either 
at  rest  or  under  fire. 

If  the  tube,  which  necessarily  forms  the  core  in  all  systems  of  wire  con- 
struction, is  to  be  subjected  to  this  law,  then  a  wire  gun  can,  in  general,  be 
made  no  stronger  than  a  built-up  one  of  the  same  thickness.     For  the  formula 

P  _3(Rf     Rq)  (q_ld\ 

(see  p.  99  of  the  printed  lecture)  giving,  as  it  does,  the  admissible  powder 
pressure,  under  the  supposition  that  the  metal  at  the  surface  of  the  bore  under- 
goes a  range  of  dilation  from  the  elastic  limit  of  tangential  compression  at 
rest  to  that  of  tangential  extension  under  fire,  applies  equally  to  built-up  and 
to  wire  guns. 

We  must  disabuse  our  minds  of  the  error,  likely  to  find  hasty  lodgment  there, 
chat  the  wire  affords  a  more  rigid  support  to  the  tube  than  surrounding  parts  of 
forged  steel  do.  The  rigidity  of  this  support  depends  upon  the  modulus  of  elas- 
ticity of  the  supporting  material,  and  that  for  steel  wire  is  no  greater  than  for 
forged  steel. 

The  wire  used  in  the  construction  of  the  guns  at  the  Watertown  Arsenal  had 
about  2,000,000  pounds  less  modulus  than  the  forged  steel  used  in  gun  construc- 
tion, although  this  wire  had  an  elastic  limit  of  100,000  pounds  and  a  tensile 
strength  of  170,000  pounds  per  square  inch. 

The  extreme  range  of  the  metal  of  the  bore  being  obtainable  in  a  built-up 
gun  of  four  concentric  cylinders,  we  can  go  no  further  either  by  greater  sub- 

« I  do  not  refer  to  the  elastic  limit  of  the  steel  wire ;  that  has  been  generally 
understated. 


140  GUN    MAKING    IN    THE    UNITED   STATES. 

division  or  by  increased  strength  of  surrounding  parts.  The  limit  of  the  play 
of  the  tube  prevents  the  utilization  of  the  great  elastic  strength  of  the  wire. 
Possible  improvement  lies  either  in  such  treatment  of  the  tube  that  its  elastic 
limit  may  be  raised  at  the  expense  of  other  qualities  considered  essential  in  the 
built-up  gun,  or  in  partial  emancipation  from  the  law  of  elastic  overstrain. 
"The  tube  may  be  made  very  thin  and  its  office  reduced  to  that  of  a  mere  core 
for  the  winding  and  medium  for  carrying  the  rifling.  All  that  may  be  required 
of  it  is  that  it  shall  stay  in  its  place,  affording  no  assistance  to  the  strength  of 
the  structure,  which  is  amply  secured  by  the  wire. 

Whether  or  not  under  these  conditions  the  tube  will  remain  intact  when  sub- 
jected to  alternating  strains  greater  than  its  elastic  limit  is  a  matter  to  be  decided 
by  experiment.  Those  of  Woehler  and  Bauschinger  indicate  that  if  strained 
without  support  through  a  range  much  greater  than  the  elastic  extension  in  one 
direction  only,  it  would  ultimately  give  way.  What  would  be  the  result  if  sup- 
ported by  an  envelope  with  a  large  reserve  of  strength  is  unknown ;  but  the 
superior  ability  of  the  wire  to  hold  it  together  after  it  has  ceased  to  afford  any 
assistance  itself  furnishes  the  hope  of  the  ultimate,  though  perhaps  slowly 
progressing,  substitution  of  wire  for  a  part  of  the  forged-steel  envelope. 

The  indications  are  that  the  art  of  gun  making  has  so  far  approached  a 
science  that  future  improvement  will  be  a  growth,  and  that  the  day  of  radical 
new  departures  is  passed. 

Capt.  Rogers  Birxie,  Ordnance  Department. 

In  closing  this  discussion  the  lecturer  wishes  first  to  remark  that  his  advocacy 
of  the  built-up  forged-steel  gun  is  based  upon  the  belief  that  it  is  preeminently 
the  gun  of  the  present ;  also  that  it  is  a  good  gun,  and  if  a  seacoast  armament  is 
to  be  provided,  the  present  development  of  this  system  of  construction  affords 
an  opportunity  for  going  to  work  at  once.  Experiments  are  costly  and  tedious, 
and  may  be  made  unending.  When  once  a  satisfactory  degree  of  excellence  has 
been  reached  the  results  should  be  made  available.  No  one  will  pretend  to  say 
that  this  gun  of  to-day  is  the  ultimatum  of  science,  or  that  experiments  and 
tests  of  promising  sj'Stems  should  be  discontinued.  I  am  not  opposed  to  tests  of 
steel-cast  guns,  but  hope  they  will  be  sufficiently  tested  to  establish  their  true 
status.  The  argument  is  directed  chiefly  against  the  delay  and  procrastination 
which  must  be  ever  present  with  us  if  we  continue  to  defer  making  guns  in 
quantity  so  long  as  plausible  designs  continue  to  be  put  forward. 

The  lecturer  finds  many  points  of  agreement  with  INIajor  Campbell  in  his 
admiration  for  the  grand  civil  establishments  that  exist  in  other  countries  for 
the  manufacture  of  ordnance,  but  it  will  scarcely  be  denied  that  each  of  these 
establishments  is  provided  with  a  special  corps  of  ordnance  designers  and  manu- 
facturers, and  that  such  men  are  the  more  valuable  in  proportion  to  their  expe- 
rience. Equally  so  is  it  necessary  to  have  an  experienced  and  trained  body  of 
officers,  who  may  intelligently  represent  the  interests  of  the  Government.  In 
every  country  officers  are  especially  assigned  to  such  duties,  whether  by  one 
designation  or  another,  and  I  believe  that  an  oi'ganization  of  this  kind  is  the 
more  effective  and  useful  in  proportion  as  its  personnel  is  able  to  devote  the  most 
exclusive  attention  to  its  special  duties.  Knowing  full  well  the  devotion  to  duty 
which  actuates  Major  Campbell  himself,  I  must  ask  him  to  credit  the  same  spirit 
to  others  of  his  profession,  and  disabuse  his  mind  of  the  suspicion  that  in  any 
path  of  duty  their  existence  is  or  can  be  "  equally  comfortable  in  failure  or 
success."  The  number  of  mixed  boards  that  have  been  appointed  in  late  years 
to  control  questions  of  armament,  and  even  the  designs  of  the  guns  to  be  manu- 
factured, does  not  permit  one  to  say  that  any  special  corps  has  controlled  the 


GUN    MAKING    IN    THE    UNITED    STATES.  141 

question.  So  far  as  contemporaneous  records  teach  us,  the  policy  of  the  Gov- 
ernment is  to  encourage  both  the  malting  of  steel  and  the  fabrication  of  guns: 
by  private  manufacturers. 

The  lecturer  must  dissent  entirely  from  the  view  advanced  by  Doctor  Wood- 
bridge,  that  dangerous  initial  strains  \A-ill  be  found  in  gun  hoops  of  steel  as  now 
manufactured  in  this  country.  Careful  experiments  have  proved  that  no  initial 
strains  existed  in  a  hoop  taken  from  the  ordinary  run  of  manufacture,  and  there 
is  otherwise  no  proof  of  their  existence ;  on  the  contrary,  the  actual  firing  tests 
of  many  hooped  guns  and  extended  experiments  show  that  the  hoops,  which  ai-e 
carefully  inspected  before  acceptance,  are  uniformly  reliable. 

The  objection  which  Doctor  Woodbridge  makes  to  the  statement  referred  to  on 
pages  22  and  23  appears  to  be  based  on  a  curious  misapiu'ehension  of  the  mean- 
ing of  the  word  "  inert "  as  used  in  the  text.  The  nearest  approach  to  the 
"  inert "  lining  tube  that  we  have  in  practice  is  that  of  a  split  tube.  Such  a  case 
is  exemplified  in  the  experimental  S-inch  rifle  con\erted  from  a  10-inch  Rodman 
gun  by  lining  with  a  steel  tube,  breech  insertion.  (See  table,  p.  26.)  The  gun 
endured  281  rounds  after  the  tube  was  cracked.  The  theoretically  inert  tube — 
that  is,  inactive  as  regards  tangential  resistance,  which  is  the  plain  meaning  of 
the  text — is  one  conceived  to  be  divided  longitudinally  by  any  number  of  me- 
ridian planes. 

It  is  a  pleasure  to  discuss  the  able  and  pertinent  criticism  in  regard  to  "  range 
of  elasticity  "  contributed  by  Mr.  Cooper.  The  comparatively  small  amount  of 
knowledge  that  exists  on  this  subject  certainly  ought  to  be  enlarged  by  extended 
experiments.  The  lecturer  does  not  hesitate  to  admit  the  force  of  this  criti- 
cism in  the  sense  that  he  has  neglected  to  take  into  account  the  laws  indicated 
by  Woehler's  and  Bauschinger's  experiments :  That  there  exists  a  "  range  of 
elasticity  "  under  incessant  changes  of  strain  which,  probably  for  all  metals,  is 
less  than  the  sum  {p-\-9).  In  practice,  however,  a  number  of  compensations 
occur  which  must  be  considered.  Taking  the  example  quoted  in  Appendix  B, 
for  instance,  it  is  stated,  page  100,  that  the  theoretically  safe  pressure  for  the 
gun  is  38,710  pounds,  for  which  the  range  of  elasticity  is  expressed  nearly  by 
the  sum  p+O  «  =40,000+17,067=57,068  pounds,  instead  of  75,000  or  80,000.  This 
results  from  the  direct  application  of  the  formulas,  and  is  indicative  of  the  aver- 
age result.  In  another  view  of  the  case  it  seems  reasonable  to  assume  that  the 
range  of  elasticity  deduced  from  experiments  like  Woehler's  may  be  increased 
in  a  built-up  gun  structure.  The  gun  is  not  subjected  to  incessant  changes  of 
strain  repeated  millions  of  times,  but  to  a  relatively  small  number  of  changes 
repeated  at  intervals ;  and  further,  in  the  whole  of  the  structure  there  is  only 
a  zone  of  metal  near  the  bore  of  tube  which  is  subjected  to  a  range  that  would 
in  cases  exceed  what  might  be  considered  a  fair  value  from  Woehler's  experi- 
ments. All  the  parts  (cylinders)  exterior  to  the  tube  act  within  a  range  that 
even  in  the  cylinder  next  the  tube  seldom  equals  the  simple  limit  expressed  by 
the  symbol  9.  That  present  practices  are  not  dangerous  seems  to  be  amply 
proved  by  the  endurance  of  hooped  guns.  I  believe  there  has  occurred  no 
instance  of  the  bursting  (splitting)  of  a  steel-hooped  gun  through  the  reinforce. 

Assuming  a  "  range  of  elasticity  "  for  the  gun  steel  to  have  been  determined 
experimentally,  no  fundamental  changes  of  formulae  need  follow.  There  would 
at  most  be  a  change  in  the  value  of  physical  constants  for  the  tube.  In  certain 
cases  there  would  follow  a  restricted  value  of  Po,  but  in  the  majority  of  cases 
the  theoretical  value  of  Pq  as  now  deduced  would  not  be  lowered.  And  there 
would,  in  any  case,  still  remain  the  superiority  claimed  over  others  for  the  built- 
up  steel  gun. 

"■  Value  given  line  8,  p.  100,  corresponding  to  P=38,910. 


142  GUN    MAKING    IN    THE    UNITED   STATES. 

The  several  quotations  made  by  Mr.  Haskell  from  the  paper  under  discussion 
warrant  the  belief  that  the  intention  of  the  lecturer  to  give  an  account  of  the 
best  performances  and  most  favorable  results  from  the  past  trials  of  the 
multicharge  system  has  been  appreciated.  A  statement  now  elicited  is  that  the 
(J  inch  gun  tested  at  Sandy  Hook,  in  1S84.  represented  the  outcome  of  the  labor 
of  thirty  years,  and  the  expenditure  of  .$300,000  in  experiment  and  construction. 
Under  these  circumstances  the  presentation  of  the  plea  that  the  gun  was  made 
of  weak  material  lays  all  the  burden  of  the  argument  upon  its  advocates.  The 
reasonable  supposition  is  that  the  question  of  strength  in  this  system  was  con- 
sidered a  matter  of  secondary  importance.  However  that  may  be,  the  argu- 
ment I  have  made  that  the  question  of  strength  in  this  gun  is  of  primary  im- 
portance loses  none  of  its  force.  The  6-inch  gun  failed  after  a  comparatively 
few  rounds.  As  regards  the  question  of  strength,  the  gun  therefore  remains  in 
the  category  of  systems  that  have  been  tried  and  have  failed.  Relatively  low 
pressures  in  this  gun  form  no  criterion  for  comparison  of  its  strength  with 
single-charged  guns.  Whether  cast  solid  or  built-up,  or  by  whatever  method 
this  gun  be  constructed,  the  irregularities  of  form  and  the  attachment  of  the 
pockets,  for  which  the  tube  must  be  cut  through  in  several  places,  present 
numerous  sources  of  weakness. 

The  ballistic  effect  realized  from  the  6-inch  multicharge  gun  would  be  a  more 
pertinent  subject  for  discussion  if  the  strength  of  the  system  had  been  estab- 
lished. In  discussing  this  question  at  any  time,  however,  a  rational  method 
embracing  all  its  bearings  should  be  adopted.  Fair  comparisons  do  not  consist 
in  selecting  one  element  out  of  many,  as  Mr.  Haskell  does.  But  even  on  his 
own  ground :  The  6-inch  Armstrong  ribband-gun,  weight  3  tons,  and  the  6.3- 
inch  Spanish  gun,  weight  six  tons,  had  each,  at  a  prior  date,  given  a  higher 
muzzle  energy  than  the  best  record  of  the  6-inch  multicharge  weighing  2.5  tons. 
The  range  of  two  guns  at  low  angles  of  elevation  affords  no  measure  of  their 
comparative  power.  All  sorts  of  absurd  deductions  would  follow  from  such  a 
premise,  e.  g..  the  comparison  which  Mr.  Haskell  attempts  to  make  between  the 
6-inch  multicharge  and  the  heavy  caliber  Krupp  gun.  In  this  case,  moreover, 
taking  the  111-pound  shot  with  which  the  stated  range  of  the  multicharge  gun 
was  obtained,  the  comparative  ability  of  this  and  the  Krupp  projectile  to  over- 
come the  resistance  of  the  air,  is  largely  in  favor  of  the  Krupp.  An  approxi- 
mately fair  comparison  could  be  made  in  this  way  in  case  the  maximum  range 
alone,  to  be  obtained  with  each  gun,  were  considered.  Taking  the  case  of  two 
projectiles  fired  from  the  same  gun,  one  of  light  weight  and  the  other  heavy, 
and  the  muzzle  energies  of  the  two  supposed  about  equal :  The  light  shot  would 
give  the  greater  range  at  small  angles  of  elevation,  while  the  heavy  shot,  owing 
to  its  greater  sectional  density,  wovild  give  the  greater  maximum  range,  and  also 
greater  penetration  and  effect  at  any  given  range.  When  a  projectile  strikes 
a  target  which  it  can  not  penetrate,  it  is  brought  to  rest  by  the  resistance  of  the 
target,  and  the  whole  of  the  stored-up  work  in  the  projectile  is  exerted  to  over- 
come the  target.  In  its  flight  through  the  air,  as  in  firing  for  range,  the  resist- 
ance of  that  medium  acts  as  a  retarding  force  only,  and  the  effective  work  of  the 
projectile  is  principally  used  up  by  the  resistance  of  the  earth  on  striking.  It 
is  apparent,  therefore,  that  the  thickness  of  the  wall  of  air  (i.  e.,  the  range) 
through  which  a  projectile  passes  does  not  afford  a  comparative  measure  of 
either  the  penetration  or  striking  energy  of  the  projectile  on  reaching  a  com- 
pact resistant  material  which  absorbs  the  momentum  of  the  projectile  within 
u  path  limited  to  a  few  feet  or  less  in  length.  The  proper  measure  of  effect 
can  only  be  based  upon  the  remaining  energy  at  any  given  distance. 

Captain  Michaelis  appears  to  have  been  led  into  error  in  comparing  the 
features  of  construction  in  the  Krupp  gun  with  our  present  designs.     The  two 


GUN   MAKING   IN    THE   UNITED    STATES.  143 

are  in  the  main  similar.  In  the  latter  the  jacket  constitutes  the  block-carrying 
cylinder,  and  performs  the  same  functions  as  the  corresponding  piece  in  the 
Krupp  gun.  In  neither  case  is  the  closure  seated  in  the  tube,  which  is  thus 
relieved  from  the  longitudinal  strain  due  to  the  pressure  on  the  breechblock. 
In  reply  to  Captain  Michaelis'  remarks  upon  the  success  of  cast  guns  in 
Sweden.  I  will  refer  to  Commander  Barber's  remarks  upon  the  same  subject, 
which  are  published  with  this  discussion. 

Captain  Butler  presents,  in  a  new  and  interesting  light,  the  authorship  of  the 
designs  of  certain  guns  which  he  names.  Ungenerous  treatment  on  my  part 
toward  himself  can  evidently  not  be  substantiated,  since  he  has  here,  for  the 
first  time,  so  far  as  I  know,  divulged  the  nature  and  extent  of  a  private  and  con- 
fidential compact  made  with  Mr.  Hunt.  He  states  that  Mr.  Hunt  is  indebted 
to  him  for  the  designs  of  these  guns.  I  am  the  more  pleased  to  be  able  to  call 
attention  to  this  because,  in  claiming  credit  for  work  done  by  officers  of  the 
Ordnance  Department,  Captain  Butler  can  by  no  means  be  left  out.  His  care- 
ful and  able  work  in  the  impro\-ement  of  methods  for  attaching  expanding 
sabots  to  the  ba.se  of  the  muzzle-loading  projectile  has  alone  given  him  a  wide 
reputation. 

A  letter  dated  Washington.  March  3,  1887,  signed  Wm.  P.  Hunt,  President 
South  Boston  Iron  Works,  was  published  in  the  National  Republican  of  March 
4,  1887.      I  take  from  that  letter  the  following  extract : 

"  In  short  the  Getty  Board  gave  me  credit  over  all  others  for  my  design  for 
a  steel  breech-loading  rifle,  and  recommended  that  a  10-inch  steel  rifle  be  made 
after  my  design.  With  this  diploma.  I  ventured  to  present  my  design  for  a 
cast-iron  12-inch  Rodman  rifle  to  the  Select  Committee  on  Ordnance,  of  which 
General  Logan  was  chairman,  and  offered  to  make  such  a  rifle  at  my  own  cost 
and  subject  to  a  firing  test  of  100  roiinds,  with  charges  of  150  pounds  of  powder 
and  a  700-pound  shot,  and  produce  a  muzzle  energy  of  10,000-foot  tons.  *  *  * 
I  then  entered  a  contract  for  five  heavy  guns,  as  follows : 

'  One  12-inch  breech-loading  Rodman  rifle,  entirely  of  cast  iron.' 

******* 

"  These  guns  were  all  designed  by  the  Ordnance  Office.  I  found  that  my 
design,  as  given  to  the  Logan  Committee,  had  been  increased  in  weight  from 
45  to  54  tons.  This  extra  weight  was  placed  mostly  at  the  breech.  Although 
the  entire  length  has  been  increased  2  calibers,  the  thickness  of  wall  at  the 
muzzle  was  left  the  same.  I  found  that  my  design,  which  provided  for  150- 
pound  charge,  was  changed  so  as  to  provide  for  265-pound  charge."     *     *     * 

From  the  information  Captain  Butler  now  gives,  we  learn  that  Mr.  Hunt  only 
spoke  of  "  my  design  "  in  the  sense  that  these  designs  were  the  property  of  the 
South  Boston  Iron  Works.  It  is  gratifying  to  know  that  the  credit  for  them 
attaches  to  an  officer  of  the  Ordnance  Department.  It  leaves  the  South  Boston 
Iron  Works  with  the  credit  of  having  made  an  excellent  casting  for  this  12-inch 
rifle — which  all  will  freely  admit.  Mr.  Hunt  gives  the  credit  for  the  design  of 
this  gini  as  actually  made  to  the  Ordnance  Office,  and  in  this  respect  is  more 
generous  than  Captain  Butler,  yet  I  may  not  do  other  than  admit  that  had  the 
latter  been  on  duty  in  the  Ordnance  Office  in  place  of  the  officers  <^  who  were 
there  at  the  time,  he  might  have  contributed  equally  well  to  the  result  accom- 
plished. 

It  may  not  be  denied  that  enormous  pressures  recorded  in  the  trials  of  cast- 
iron  rifles,  which  are  inconceivable  when  regarded  as  a  register  of  the  true  prcs- 

«  The  writer  was  "  employed  elsewhere  "  at  that  time,  and  took  no  part  in  the 
alterations  and  improvements  made  in  Mr.  Hunt's,  or  rather  Captain  Butler's, 
design  of  the  gun  in  question. 


144  GUN    MAKING    IN    THE    UNITED   STATES. 

su)-c  in  the  bore,  Lave  been  repeatedly  used  as  an  argument  in  their  favor.  In 
tlie  table  given,  page  12G,  Getty  Board,  the  compilation  of  which  it  appears  is 
due  to  Captain  lUitler  himself,  there  is  a  selected  record  of  twenty-seven  pres- 
sures, of  which  eleven  exceed  08,tK;K)  pounds,  and  no  doubt  is  thrown  by  the  com- 
piler upon  the  authenticity  of  two  records  of  1.jO,000  pounds,  two  of  200,000 
pounds,  and  one  of  240,000  pounds.  Is  it  not  reasonable  to  suppose  that  the 
pressure-gauges  were  more  truthful  in  their  record  on  June  14,  1870,  when  the 
following  results  were  obtainedV  Seven  rounds  were  fired  on  that  day  from 
8-inch  rifle  No.  2,  rounds  numbered  836  to  842,  inclusive;  the  charge  througii- 
out  was  15  pounds  of  powder  with  Dyer  solid  shot  of  1.50  pounds  weight, 
and  the  pressures  were,  respectively,  21,000,  30,000,  23,000,  25,000,  18,000,  25,000, 
28,000. 

Individual  opinion  is.  I  suppose,  always  open  to  the  charge  of  being  influenced 
by  prejudice.  However,  if  the  facts  of  a  given  case  are  substantiated,  the  public 
may  judge  for  itself,  and,  noting  that  Captain  Butler  has  not  refuted  any  of  the 
facts  upon  which  were  based  my  unfavorable  conclusions  upon  the  merits  of 
cast-iron  rifles,  I  am  satisfied  to  let  the  opinions  stand  for  what  they  are  worth. 
The  principal  causes  which  led  to  the  cessation  of  the  manufacture  of  cast-iron 
rifles  in  this  country  were  the  findings  of  the  Select  Committee  on  Ordnance, 
1SG9,  and  the  unfavorable  results  of  the  trials  of  guns  which  I  have  authentic- 
ally given,  and  no  defense  is  needed  for  stating  these  plain  facts  of  history. 

In  conclusion  I  will  express  my  thanks  for  the  kind  appreciation  of  the 
gentlemen  who  have  taken  part  in  this  discussion,  and,  at  the  same  time,  my 
regrets  that  I  have  been  unable  to  discuss  more  fully  the  arguments  made  for 
and  against  the  views  presented  in  the  lecture. 

War  Department, 

Office  of  the  Chief  of  Ordnance, 

Washington,  May  13,  1907. 

Reprinted  from   the   Journal  of  the  Military   Service   Institution  ;   Includes   corrections 
made  by  the  author  on  May  1,  1907. 
FouM  No.  1755. 
Revised  May  1,  1907. 
Ed.  May  13-07—250. 

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